Ligand-Accelerated Cross-Coupling of C(sp2)–H Bonds with Arylboron Reagents

Keary M. Engle, Peter S. Thuy-Boun, Michael Dang, and Jin-Quan Yu

J. Am. Chem. Soc., 2011, 133, 18183–18193

DOI: 10.1021/ja203978r

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 may also be beneficial when applied to catalytic cross-coupling conditions under an oxygen atmosphere thus providing alternative "Green" conditions for this biaryl transformation.

Rhodium-Catalyzed Reductive Cleavage of Carbon−Cyano Bonds with Hydrosilane: A Catalytic Protocol for Removal of Cyano Groups

Mamoru Tobisu, Ryo Nakamura, Yusuke Kita and Naoto Chatani

J. Am. Chem. Soc., 2009, 131, 3174–3175

DOI: 10.1021/ja810142v

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).