Catalyst-controlled stereoselective carbon-heteroatom bond formations by N-heterocyclic carbene (NHC) organocatalysis

The development of synthetic strategies towards enantioselective access to carbon-heteroatom bonds by means of catalyst control continues to receive considerable interest in organic chemistry. Over the past decades, N-heterocyclic carbene (NHC) organocatalysis has witnessed extensive exploration for a rapid assembly of asymmetric carbon-heteroatom bonds in a wide range of novel chemical transformations. A diverse set of activation modes and NHC-derived intermediates, such as Breslow intermediates, acyl azoliums, etc., that feature distinct nucleophilicity or electrophilicity have been demonstrated to exhibit substantial potential in the construction of carbon-heteroatom bonds. This review will summarize recent advances in stereoselective carbon-heteroatom bond forming reactions, including C-N, C-O, C-S, C-F, C-P, etc., that were enabled by NHC organocatalysis with a focus on new activation modes and reactive intermediates, aiming to inspire unique insights into the preparation of chiral functional molecules by the use of NHC organocatalysis.