Asymmetric Pd-NHC*-catalyzed coupling reactions

Kündig, E. Peter; Jia, Yixia; Katayev, Dmitry; Nakanishi, Masafumi

doi:10.1351/PAC-CON-12-02-10

Pure Appl. Chem., 2012, Vol. 84, No. 8, pp. 1741-1748

http://dx.doi.org/10.1351/PAC-CON-12-02-10

Published online 2012-07-01

Asymmetric Pd-NHC*-catalyzed coupling reactions

E. Peter Kündig*, Yixia Jia, Dmitry Katayev and Masafumi Nakanishi

Department of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland

Abstract: Very high asymmetric inductions result in the Pd-catalyzed intramolecular arylation of amides to give 3,3-disubstituted oxindoles when new in situ-generated chiral N‑heterocyclic carbene (NHC*) ligands are employed. Structural studies show that conformational locking to minimize allylic strain is the key to understanding the function of these ligands. New applications of these ligands in the frontier area of asymmetric coupling reactions involving C(sp³)–H bonds are detailed. Highly enantioenriched fused indolines are accessible using either preformed- or in situ-generated Pd-NHC* catalysts. Remarkably, this occurs at high temperature (140–160 °C) via excellent asymmetric recognition of an enantiotopic C–H bond in an unactivated methylene unit.