Book review, Modern Catalytic Methods for Organic Synthesis with Diazo Compounds

Abstract

Dirhodium tetrakis(S-(N-dodecylbenzenesulfonyl)prolinate) (Rh 2 (S-DOSP) 4) catalyzed decomposition of methyl aryldiazoacetates in the presence of 2-substituted pyrrolidines results in highly diastereoselective and enantioselective C−H insertions. These reactions can proceed with impressive levels of double stereodifferentiation and kinetic resolution, which allows for three stereocenters to be controlled during the C−H insertion step. In recent years there has been considerable interest in the development of new methods for catalytic C-H activation. 1 One particularly attractive method is the C-H insertion by metal carbenoid intermediates. 2 The intramolecular version of this reaction is well established and has been elegantly used in a number of total syntheses. 2 Recently, the rhodium carbenoids derived from aryldiazoacetates have been demonstrated to be exceptional at intermolecular C-H insertion. 3,4 A notable example is the Rh 2 (S-DOSP) 4 catalyzed reaction of N-BOC pyrrolidine which leads to a highly regio-and stereoselective C-H activation (Scheme 1). 3d This reaction can be considered as a surrogate for an asymmetric Mannich reaction. 5 In this Letter we describe that impressive double stereo-differentiation and kinetic resolution can occur during the catalytic asymmetric C-H insertion step (Scheme 2). 6 This allows for three or even four stereocenters to be controlled during the C-H insertion. These studies highlight the remarkable stereoselectivity that is possible in the reactions of aryldiazoacetates and offer considerable promise for their utilization in organic synthesis. (1) (a) Shilov, A. E.; Shul′pin, G. B. Chem. ReV. 1997, 97, 2879. (b) Arndtsen, B. A.; Bergman, R. G.; Mobley, T. A.; Peterson, T. H.