tag:blogger.com,1999:blog-7870920377931633232024-02-02T09:36:23.228-08:00Metal-Mediated Organic ReactionsMMOR is a summary of literature relating to organic reactions that are either mediated or catalyzed by organometallic or Lewis acid catalystsMetal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-787092037793163323.post-84341050430558111662011-12-18T19:46:00.000-08:002011-12-22T10:36:55.311-08:00Ligand-Accelerated Cross-Coupling of C(sp2)–H Bonds with Arylboron Reagents<div class="separator" style="clear: both; text-align: center;">
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<span style="display: inline ! important; float: none; font-family: 'Trebuchet MS',Arial,Helvetica,sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: bold; letter-spacing: normal; line-height: 16px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;">Keary M. Engle, Peter S. Thuy-Boun, Michael Dang, and Jin-Quan Y<cite>u</cite></span><span style="background-color: white; color: #333333; display: inline ! important; float: none; font-family: 'Trebuchet MS',Arial,Helvetica,sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: bold; letter-spacing: normal; line-height: 16px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"></span></div>
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<span style="background-color: white; color: #333333; display: inline ! important; float: none; font-family: 'Trebuchet MS',Arial,Helvetica,sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: bold; letter-spacing: normal; line-height: 16px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><cite></cite></span><cite>J. Am. Chem. Soc.</cite>,<span class="Apple-converted-space"> </span><span class="citation_year" style="font-weight: bold;">2011</span>,<span class="Apple-converted-space"> </span><span class="citation_volume" style="font-style: italic;">133</span><span class="Apple-converted-space">, </span>18183–18193</div>
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<b>DOI:<span class="Apple-converted-space"> </span></b><a href="http://pubs.acs.org/doi/abs/10.1021/ja203978r" target="_blank">10.1021/ja203978r</a></div>
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<span style="background-color: black; color: white; display: inline ! important; float: none; font-family: 'Trebuchet MS',Arial,Helvetica,sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 500; letter-spacing: normal; line-height: 22px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"></span></div>
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<span style="background-color: black; color: white; display: inline ! important; float: none; font-family: "Trebuchet MS",sans-serif; font-size: 13px; font-style: normal; font-variant: normal; letter-spacing: normal; line-height: 16px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span style="font-size: small;">A palladium catalyzed C–H functionalization between Molander's arylboronate reagents and phenylacetic acid derivatives was demonstrated. From extensive screening, this synthetic method was found to be efficacious utilizing Ac-Ile-OH as the ligand and Ag2CO3 as the oxidant. As a result, a high yielding and experimentally straightforward procedure has evolved into a useful cross-coupling protocol between arylacetic acid derivatives and aryltrifluoroborates. The authors also found that this ligand accelertated process has superb functional group tolerance and </span></span><span style="background-color: black; color: white; display: inline ! important; float: none; font-family: "Trebuchet MS",sans-serif; font-size: 13px; font-style: normal; font-variant: normal; letter-spacing: normal; line-height: 16px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span style="font-size: small;">may also be beneficial when applied to catalytic cross-coupling conditions under an oxygen atmosphere thus providing alternative "Green" conditions for this biaryl transformation.</span></span></div>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com1tag:blogger.com,1999:blog-787092037793163323.post-59357605586063257312011-12-02T18:30:00.001-08:002011-12-12T18:26:03.471-08:00A Highly Enantio- and Diastereoselective Molybdenum-Catalyzed Asymmetric Allylic Alkylation of Cyanoester<div class="separator" style="clear: both; text-align: center;">
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<span class="Apple-style-span" style="color: orange; font-family: Arial,Helvetica,sans-serif;"><span class="Apple-style-span"><b>Conditions:</b></span></span><br />
<span class="Apple-style-span" style="color: orange; font-family: Arial,Helvetica,sans-serif;">10 mol% Mo(CO)6, 15 mol% ligand, </span><span class="Apple-style-span" style="color: orange; font-family: Arial,Helvetica,sans-serif;">10 mol% NaH, BSA, THF, 60 deg C</span><br />
<span class="Apple-style-span" style="color: orange; font-family: Arial,Helvetica,sans-serif;">99% yield, 20/1 Branched/Linear, 11/1 dr, 97% ee</span><br />
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<span class="Apple-style-span" style="font-family: Arial,Helvetica,sans-serif; font-weight: bold;"><span class="Apple-style-span" style="background-color: black; color: white; font-weight: normal;">Barry M. Trost, John R. Miller, and Christopher M. Hoffman, Jr</span></span><br />
<span class="Apple-style-span" style="background-color: black; color: white;"><span class="Apple-style-span"><cite>J. Am. Chem. Soc.</cite></span><span class="Apple-style-span">, </span><span class="Apple-style-span"><span class="citation_year" style="font-weight: bold;">2011</span></span><span class="Apple-style-span">, </span><span class="Apple-style-span"><span class="citation_volume" style="font-style: italic;">133, </span></span><span class="Apple-style-span">8165–8167</span></span><br />
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<span class="Apple-style-span" style="background-color: black; color: white;"><b>DOI: </b><a href="http://pubs.acs.org/doi/abs/10.1021/ja2029602" target="_blank">10.1021/ja2029602</a></span></div>
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<span class="Apple-style-span" style="background-color: black; color: white; font-family: Arial,Helvetica,sans-serif; line-height: normal;">Summary: An <span class="Apple-style-span" style="font-family: arial; line-height: 18px;">efficacious</span> Mo-catalyzed enantioselective allylation of various cyanoester nucleophiles provided a number of highly functionalized branched cyanoesters containing a quaternary carbon stereocenter. This synthetic method generates the desired allylic cyanoesters products with high yield, chemoselectivity, diastereoselectivity and enantioselectivity.</span></div>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com0tag:blogger.com,1999:blog-787092037793163323.post-47005314986575945292011-11-29T15:23:00.000-08:002011-12-18T19:24:44.582-08:00Reaction Development and Mechanistic Study of a Ruthenium Catalyzed Intramolecular Asymmetric Reductive Amination en Route to the Dual Orexin Inhibitor Suvorexant (MK-4305)<div id="citation" style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 10px; text-align: left;">
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<span class="Apple-style-span" style="font-size: small;"><cite><span class="Apple-style-span" style="background-color: black; color: white; font-style: normal; font-weight: bold;">Neil A. Strotman, Carl A. Baxter, Karel M. J. Brands, Ed Cleator, Shane W. Krska, Robert A. Reamer, Debra J. Wallace, Timothy J. Wright</span></cite></span></div>
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<span style="font-size: small;"><a href="http://pubs.acs.org/doi/abs/10.1021/ja202358f" target="_blank"><span class="Apple-style-span" style="background-color: black; color: white;"><cite>J. Am. Chem. Soc.</cite>, <span class="citation_year" style="font-weight: bold;">2011</span>, <span class="citation_volume" style="font-style: italic;">133</span>, 8362–8371</span></a></span></div>
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<span style="font-size: small;"><i><span class="Apple-style-span" style="font-style: normal;"><a href="http://pubs.acs.org/doi/abs/10.1021/ja202358f" target="_blank"><span class="Apple-style-span" style="background-color: black; color: orange;"><b>DOI: </b>10.1021/ja202358f</span></a></span></i></span></div>
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<span class="Apple-style-span" style="font-family: 'Lucida Grande',Arial,'Lucida Sans Unicode',sans-serif; font-size: small; line-height: 19px;"><span class="Apple-style-span" style="background-color: black; color: white;">Summary: Suvorexant (MK-4305) is a potent dual Orexin antagonist under development for the treatment of sleep disorders at Merck. The key transformation is an intramolecular asymmetric Ru-catalyzed transfer hydrogenation (using a modified Noyori RuCl(p-cymene)(DPEN) complex) of an in-situ generated cyclic imine resulting in the formation of the desired diazepane in 97% yield and 94.5% ee. Mechanistic studies have revealed that CO2 (derived from the formic acid) has pronounced effect on reaction outcome. Studies have determined that the efficiency of the Ru-catalyst, the composition of the resulting amine (i.e. carbamate formation), and the reaction kinetics are mediated by the amount of CO2 generated during the reaction. The efficiency of the reductive-amination can be enhanced by either purging of the CO2 or by trapping the thus formed nucleophilic secondary amines.</span></span></div>
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<span style="font-size: small;"><b><span class="Apple-style-span" style="background-color: black; color: white;">References:</span></b></span><br />
<span style="font-size: small;"><b><span class="Apple-style-span" style="background-color: black; color: white;"><br /></span></b></span></div>
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<span data-mce-style="color: #333399;" style="font-size: small;"><span class="Apple-style-span" style="background-color: black; color: white;">1) <a data-mce-href="http://pubs.acs.org/doi/abs/10.1021/op1002853" href="http://pubs.acs.org/doi/abs/10.1021/op1002853" target="_blank" title="The First Large-Scale Synthesis of MK-4305: A Dual Orexin Receptor Antagonist for the Treatment of Sleep Disorder"><cite style="border-bottom: 1px dashed blue;">Org. Process Res. Dev.</cite>, 2011, 15, 367–375 (<b>DOI: </b>10.1021/op1002853)</a></span></span></div>
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<span class="Apple-style-span" style="font-size: small;"><span class="Apple-style-span" style="background-color: black; color: white;">2) <a data-mce-href="http://www.kanto.co.jp/english/siyaku/pdf/fuseishokubai_02.pdf" href="http://www.kanto.co.jp/english/siyaku/pdf/fuseishokubai_02.pdf">http://www.kanto.co.jp/english/siyaku/pdf/fuseishokubai_02.pdf</a></span></span></div>
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</div>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com0tag:blogger.com,1999:blog-787092037793163323.post-56611064828787564422009-03-08T15:06:00.000-07:002011-12-11T11:17:24.115-08:00Rhodium-Catalyzed Reductive Cleavage of Carbon−Cyano Bonds with Hydrosilane: A Catalytic Protocol for Removal of Cyano Groups<br />
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Mamoru Tobisu, Ryo Nakamura, Yusuke Kita and Naoto Chatani<br />
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<cite>J. Am. Chem. Soc.</cite>, <span class="citation_year">2009</span>, <span class="citation_volume">131</span>, 3174–3175</div>
<div id="doi">
<a href="http://pubs.acs.org/doi/abs/10.1021/ja810142v"><strong>DOI: </strong>10.1021/ja810142v</a></div>
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<span style="font-family: verdana;">Summary: Recently, transition metal activation of the C-CN bond has been an area of intense synthetic activity. Much of the previous work has been centered around Ni(0) mediated C-C bond formation. The Chatani group has developed a rhodium-catalyzed hydrosilane mediated reductive cleavage of the C−CN bond. The reaction has a large synthetic scope including decyanation of aryl- and alkyl nitriles. Additionally, the reaction has a very good functional group tolerence and can be performed in the presence of ester, ether, amino and amide groups. This synthetic method was also demonstrated in several examples where a cyano group was present as a removable ortho-directing group (via a C-H functionalization process).</span></div>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com0tag:blogger.com,1999:blog-787092037793163323.post-7630314655057151872009-03-07T14:01:00.000-08:002011-12-11T10:56:15.662-08:00Efficient Boron−Copper Additions to Aryl-Substituted Alkenes Promoted by NHC−Based Catalysts. Enantioselective Cu-Catalyzed Hydroboration Reactions<br />
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Yunmi Lee and Amir H. Hoveyda<br />
<cite>J. Am. Chem. Soc.</cite>, <span class="citation_year">2009</span>, <span class="citation_volume">131</span>, 3160–3161<br />
<a href="http://pubs.acs.org/doi/abs/10.1021/ja809382c">DOI:10.1021/ja809382c</a><br />
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Summary: This paper describes the development of a Cu-catalyzed formal hydroboration of olefinic substrates (styrene derivatives). The reaction is highly regio and stereoselective affording the organoboron products in moderate to high yield. The reaction utilizes a copper NHC complex (0.5-7.5 mol%) and pinacolatoboron as the boron source. In the asymmetic variant the er's range from 86/14 to 99/1.Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com1tag:blogger.com,1999:blog-787092037793163323.post-12111391591117552442007-05-06T11:43:00.001-07:002011-12-12T17:54:22.272-08:00Rhodium-Catalyzed Asymmetric Synthesis of 3,3-Disubstituted 1-Indanones<div class="separator" style="clear: both; text-align: center;">
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<span class="Apple-style-span" style="font-family: arial; font-size: 16px; font-weight: bold;">Ryo Shintani, Keishi Takatsu, Tamio Hayashi</span><br />
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<span style="font-size: 100%;"><span style="font-family: arial;"><span style="font-style: italic;">Angewandte Chemie International Edition</span>; <span style="font-weight: bold;">2006</span>, <span style="font-style: italic;">46</span>, 3537-3737<br />DOI: <a href="http://www3.interscience.wiley.com/cgi-bin/abstract/114206033/ABSTRACT">10.1002/anie.200700226</a></span></span><br />
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<span style="font-size: 100%;"><span style="font-family: arial;"><span style="font-family: verdana;">Summary: Chiral</span></span></span><span style="font-family: verdana;"> indanones that are difficult to obtain by other synthetic methods can be prepared via an enantioselective addition of aryl boronates to aryl alkynyl ketones. </span><span style="font-family: verdana;">The resulting substituted indanones arrive from a tandem Rh-catalyzed C-H functionalization-cyclization sequence. </span><span style="font-family: verdana;">This reaction utilizes a rhodium catalyst system with the asymmetric induction originating from a chiral bisphosphine ligand. </span></div>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.comtag:blogger.com,1999:blog-787092037793163323.post-9926151959020947402007-05-05T06:38:00.000-07:002011-12-12T18:22:31.760-08:00Palladium-Catalyzed Benzene Arylation: Incorporation of Catalytic Pivalic Acid as a Proton Shuttle and a Key Element in Catalyst Design<div class="separator" style="clear: both; text-align: center;">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSQQiyxc8mlM78RFKa-7_ExW1NLPIPDIXuM_PgnIOp-PeHSNvofndBEXCp97HS4u7NXECER8GWNaFmnPU_qitEfX3Tdq0IIkmvrxjzLBWFj69S1DqdljhGH1NQmrUqcqtrqsCMDaZslvsw/s1600/Pd+C-H+activation.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="404" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSQQiyxc8mlM78RFKa-7_ExW1NLPIPDIXuM_PgnIOp-PeHSNvofndBEXCp97HS4u7NXECER8GWNaFmnPU_qitEfX3Tdq0IIkmvrxjzLBWFj69S1DqdljhGH1NQmrUqcqtrqsCMDaZslvsw/s640/Pd+C-H+activation.bmp" width="640" /></a></div>
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<b style="font-size: 16px;">Marc Lafrance and</b><span class="Apple-style-span" style="font-size: 16px;"> </span><au style="font-size: 16px;"><b>Keith Fagnou</b></au></div>
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<span style="font-size: 100%;"><i>J. Am. Chem. Soc.,</i> <b><vol>2006, </vol></b><vol style="font-style: italic;">128</vol><iss></iss>, <spn>16496</spn> -<epn>16497</epn></span></div>
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<a href="http://pubs.acs.org/doi/abs/10.1021/ja067144j"><span style="font-size: 100%;">DOI: 10.1021/ja067144j</span></a></div>
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<span style="font-size: 100%;"><span style="font-family: verdana;">Summary: C-H activation processes represent an important area of synthetic exploration since the starting materials required are less functionalized and potentially less expensive. A Pd-pivalic acid co-catalyst system has been utilized in the direct arylation of benzene and aryl bromides. Experimental and computational studies indicate that the pivalate anion is a key component in the palladation/C-H bond breaking event. Additionally, aryl chorides and iodides were found to be poor substrates.</span></span></div>
<span style="font-size: 100%;"><br /><span style="font-family: verdana;">8 examples: 55-85%</span></span></div>
</div>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com0tag:blogger.com,1999:blog-787092037793163323.post-49047676987699113402007-04-29T07:32:00.001-07:002011-12-12T12:19:25.216-08:00C-C Bond Activation with Selective Functionalization: Preparation of Unsymmetrical Biaryls from Benzonitriles<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlXh2vkNlElatLlqLFGrqQEvf_CGyVXtZ6Vj6mpljDnZihLQO2mP7BQqZBW_DC0zzH0ajubk3HP1Rp7cN43O_asFEWS8nKviIQlfdwY5PdA9jtZ690Vsw5XV4t5yppp87lisj25C5N1FtB/s1600/Ni+ArCN.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="360" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlXh2vkNlElatLlqLFGrqQEvf_CGyVXtZ6Vj6mpljDnZihLQO2mP7BQqZBW_DC0zzH0ajubk3HP1Rp7cN43O_asFEWS8nKviIQlfdwY5PdA9jtZ690Vsw5XV4t5yppp87lisj25C5N1FtB/s640/Ni+ArCN.bmp" width="640" /></a></div>
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<span style="font-family: verdana;">Joseph A. Miller</span><br />
<span style="font-family: verdana; font-style: italic;">Tetrahedron Letters</span><span style="font-family: verdana;">; </span><span style="font-family: verdana; font-weight: bold;">2001</span><span style="font-family: verdana;">, </span><span style="font-family: verdana; font-style: italic;">42</span><span style="font-family: verdana;">, 6991–6993</span><br />
<span class="Apple-style-span" style="background-color: black;"><span class="Apple-style-span" style="color: white;"><span style="font-family: verdana;">DOI:</span><a href="http://dx.doi.org/10.1016/S0040-4039(01)01476-9" id="ddDoi" rel="nofollow" style="border-bottom-width: 0px; border-color: initial; border-left-width: 0px; border-right-width: 0px; border-style: initial; border-top-width: 0px; box-sizing: border-box; font-family: arial, verdana, helvetica, sans-serif; text-align: -webkit-left;" target="doilink">10.1016/S0040-4039(01)01476-9</a></span></span><br />
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<span style="font-family: verdana;">Summary: Nickel catalysts have been known to coordinate and subsequently activate the C-CN bond of nitrile compounds. However, a practical procedure to perform a cross-coupling reaction with these substrates and an appropriate organometallic was unknown until the present work. Thus, reaction of a benzonitrile with an aryl Grignard derivative in the presence of a Ni catalyst, such as [NiCl2(PMe3)2], provides the corresponding unsymmetrical biaryl in high yield and with high selectivity. Ligand screening found that trimethylphosphine was the most effective ligand. The Grignard reagent was modified (for example, ArMgO</span><span style="font-family: verdana; font-style: italic;">t</span><span style="font-family: verdana;">-Bu) to reduce the amount of direct addition of the organomagnesium reagent to the nitrile. This group has also expanded the methodology to alkyl, alkenyl, and alkynyl organometallics.</span></div>
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16 examples, 69-97% yield<br />
<a href="http://144.206.159.178/FT/1010/43321/785803.pdf" target="_blank">PDF</a><br />
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<a href="http://dx.doi.org/10.1016/S0040-4039%2801%2901476-9" set="yes" target="doilink"></a>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.comtag:blogger.com,1999:blog-787092037793163323.post-70703465886380409372007-04-28T15:05:00.002-07:002011-12-10T13:48:42.313-08:00Rhodium-Catalyzed Arylative and Alkenylative Cyclization of 1,5-Enynes Induced by Geminal Carbometalation of Alkynes<div class="separator" style="clear: both; text-align: center;">
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<au style="font-family: verdana;">Yiyun Chen and</au><span style="font-family: verdana;"> </span><au style="font-family: verdana;">Chulbom Lee</au><i style="font-family: verdana;"><ti><br />J. Am. Chem. Soc.,</ti></i><span style="font-family: verdana;"> </span><b style="font-family: verdana;"><vol>2006, </vol></b><vol style="font-family: verdana; font-style: italic;">128</vol><iss style="font-family: verdana;"></iss><span style="font-family: verdana;">, </span><spn style="font-family: verdana;">15598</spn><span style="font-family: verdana;"> -</span><epn style="font-family: verdana;">15599</epn><span class="text" style="font-family: verdana;"><span class="text"><br />DOI: <a class="link" href="http://pubs.acs.org/doi/abs/10.1021/ja067125%2B" target="_blank">10.1021/ja067125+</a></span></span><br />
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Summary: A Rh(I)-catalyzed alkyne-boronic acid addition-cyclization has been developed to afford various alkenyl ketone derivatives. The reaction is believed to proceed through a metal vinylidene complex which eventually undergoes an intramolecular conjugate addition to provide the desired cyclized ketone adduct.</div>
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<span style="font-family: verdana;">10 examples : Reaction Optimization (0-65% yield)</span><br />
<span style="font-family: verdana;">19 examples: Reaction Scope (11-84% yield)</span><br />
<span style="font-family: verdana;">2 examples: Deuterated substrates for mechanistic studies</span>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.comtag:blogger.com,1999:blog-787092037793163323.post-26824088589629937912007-04-28T12:35:00.000-07:002011-12-15T07:56:02.497-08:00Gold(I)-Catalyzed Intramolecular Hydroamination of Alkenyl Carbamates<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7tAgCUbDc6W2nYMYkwTgICCjsjii-pp5dfmFeH5NrRwvzMZcCYUi037pAct_VkdG0PGdk7UGXvBUVBOEYmSPqB5x3TADxHoqtpd7Z21jLJctFIfa0HA7jBJ-UNmUypWKiOvZ47yoYsuvX/s1600/Au.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="456" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7tAgCUbDc6W2nYMYkwTgICCjsjii-pp5dfmFeH5NrRwvzMZcCYUi037pAct_VkdG0PGdk7UGXvBUVBOEYmSPqB5x3TADxHoqtpd7Z21jLJctFIfa0HA7jBJ-UNmUypWKiOvZ47yoYsuvX/s640/Au.bmp" width="640" /></a></div>
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<span style="font-family: verdana;">Xiaoqing Han, Ross A. Widenhoefer</span><span style="font-family: verdana; font-size: 100%;"><span style="font-weight: bold;"><br /></span><span style="font-style: italic;">Angewandte Chemie International Edition;</span></span><span style="font-family: verdana; font-size: 100%; font-weight: bold;"><b><b></b></b></span><span style="font-family: verdana; font-size: 100%;"><b><b></b></b></span><span style="font-family: verdana; font-size: 100%; font-weight: bold;"><b><b></b></b></span><span style="font-family: verdana;"> </span><span style="font-family: verdana; font-weight: bold;">2006</span><span style="font-family: verdana;">, </span><span style="font-family: verdana; font-style: italic;">45</span><span style="font-family: verdana;">, 1747-1749</span><br />
<span style="font-family: verdana;">DOI: </span><a href="http://www3.interscience.wiley.com/cgi-bin/abstract/112417940/ABSTRACT" style="font-family: verdana;">10.1002/anie.200600052</a><br />
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<span style="font-family: verdana;">Summary: This paper describes the intramolecular gold(I)-catalyzed hydroamination of olefinic carbamates for the preparation of functionalized saturated nitrogen heterocycles. The products incorporate either five or six membered ring system </span><span style="font-family: verdana; font-style: italic;">via</span><span style="font-family: verdana;"> an exo-trig cyclization. This Au(I)-catalyzed reaction overcomes several limitations of the corresponding Pt-mediated annulation such as substrate scope and reaction temperature.</span><span style="font-family: verdana;"> Determination of the optimized conditions (ligand and solvent studies - 8 examples: 7-98% yield) plus 15 additional examples using the optimized conditions: 59-97% yield</span></div>
<a href="http://www.blogger.com/blogger.g?blogID=787092037793163323" name="keywords"><br /></a>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com0tag:blogger.com,1999:blog-787092037793163323.post-80269543003395048492007-04-01T17:46:00.000-07:002011-12-15T07:27:31.211-08:00Palladium-Catalyzed Kumada-Corriu Cross-Coupling Reactions at Low Temperatures Allow the Use of Knochel-type Grignard Reagents<div class="separator" style="clear: both; text-align: center;">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiin7Ufql2rOBHEmc04RPV0UhoY_dCEmCn9lXKemAwBxGfWkfrQyfYsDn0sxds-8CbymnozqPqa8hkuonm0C3aIZtgLSPC4rbfNzDRixHNoLFWFYmZoxrt4mDi8tIB6SihAT-ZPeFOoLftP/s1600/Pd+Buchwald.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="264" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiin7Ufql2rOBHEmc04RPV0UhoY_dCEmCn9lXKemAwBxGfWkfrQyfYsDn0sxds-8CbymnozqPqa8hkuonm0C3aIZtgLSPC4rbfNzDRixHNoLFWFYmZoxrt4mDi8tIB6SihAT-ZPeFOoLftP/s640/Pd+Buchwald.bmp" width="640" /></a></div>
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<span style="font-family: arial;">Ruben Martin and Stephen L. Buchwald<span style="font-style: italic;"><br /></span></span><span class="textsmall" style="font-family: verdana;"><span style="font-style: italic;">J. Am. Chem. Soc</span>.; <b>2007, </b><span style="font-style: italic;">129</span>, 3844 - 3845.<br />DOI: <a href="http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/ja070830d">10.1021/ja070830d</a></span><span style="font-family: arial;"> </span><br />
<span style="font-family: arial;">Summary: Biaryl compounds are important structural elements in natural products and medicinally useful drug substances. This paper reports a useful advance in the </span><span style="font-family: arial;">palladium-catalyzed Kumada-Corriu biaryl cross-coupling reaction. </span><span style="font-family: arial;">The significance of this work is derived from the ability to conduct the reactions at low temperature (-20 to -65 deg C). This was made possible by (i) the application of Knochel's methodology, to form the desired Grignard reagents, containing in many cases reactive functional groups on the aromatic ring and (ii) the proper choice of biaryl phosphine ligand. Martin and Buchwald were able to take advantage of this chemistry and and prepare a variety of biaryl compounds including </span><span style="font-family: arial;"><span style="font-family: verdana;">heterocyclic and polyfluoro biaryls. Screening of aryl iodides and triflates with various ligands revealed that superior conditions utilized aromatic iodides in conjunction with either DavePhos or S-Phos. Nitriles, esters, acetals, and amines are compatible under these conditions.</span></span><br />
<span style="font-family: arial;"><br /><span style="font-family: verdana;">21 examples: 55-96% yield</span></span><span style="font-family: arial;"><br /></span>Metal-Mediated Organic Reactionshttp://www.blogger.com/profile/06821549835939671420noreply@blogger.com