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.

A Highly Enantio- and Diastereoselective Molybdenum-Catalyzed Asymmetric Allylic Alkylation of Cyanoester

Conditions:
10 mol% Mo(CO)6, 15 mol% ligand, 10 mol% NaH, BSA, THF, 60 deg C
99% yield, 20/1 Branched/Linear, 11/1 dr, 97% ee

Barry M. Trost, John R. Miller, and Christopher M. Hoffman, Jr
J. Am. Chem. Soc., 2011, 133, 8165–8167

DOI: 10.1021/ja2029602

Summary: An efficacious 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.