Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

Abstract

The transition metal-catalyzed addition of C–H bonds to carbonyls, imines and related polarized π-bonds has emerged as a particularly efficient and powerful approach for the construction of an incredibly diverse array of heteroatom substituted products. Readily available and stable inputs are typically employed, and reactions often proceed with very high functionality group compatibility and without the production of waste byproducts. Additionally, many transition metal-catalyzed C–H bond additions to polarized π-bonds occur within cascade reaction sequences to provide rapid access to a diverse array of different heterocyclic as well as carbocyclic products. This review highlights the diversity of transformations that have been achieved, catalysts that have been used, and types of products that have been prepared through the transition metal catalyzed addition of C–H bonds to carbonyls, imines and related polarized π-bonds.

Cp*RhIII‐Catalyzed Directed Amidation of Aldehydes with Anthranils

“…Recently, several reports disclosed that Cp*Rh III complexes undergo chelation-assisted directed electrophilic metalation of ortho-C(sp 2 )-H bonds to form a variety of aryl/alkenyl-rhodium complexes, [19] which are coupled to a range of functional groups [20] including azides, [21] anthranils, [22] and nitrosobenzenes. [23] Owing to their significant coordinating property and cleavable polar N-O bond, we contemplated that anthranils may serve as substrates in the C-H amination reaction of aldehydes.…”

Cobalt(III)‐Catalyzed C−H Amidation of Dehydroalanine for the Site‐Selective Structural Diversification of Thiostrepton

“…For C(sp 2 )−H functionalization of the Dhas of 1 , we evaluated a range of coupling partners, including isocyanates and electrophilic alkenes such as enones, acrylates, and maleimides . Unfortunately, under a variety of conditions and with different transition metal catalysts, little to no desired products were obtained, often with significant degradation of the natural product.…”

Convergent Synthesis of α‐Branched Amines by Transition‐Metal‐Catalyzed C−H Bond Additions to Imines

“…In recent years, our laboratory has reported a general strategy for heterocycle synthesis by cascade C−H bond additions to polarized π bonds followed by cyclization with the directing group for C−H functionalization . In 2013 we extended this annulation approach to imine additions for the synthesis of highly substituted pyrroles 30 (Scheme ) .…”