Mechanism of NHC-Catalyzed Conjugate Additions of Diboron and Borosilane Reagents to α,β-Unsaturated Carbonyl Compounds.

ABSTRACT: Broadly applicable enantioselective C-B and C-Si bond-forming processes catalyzed by an N-heterocyclic carbene (NHC) were recently introduced; these boryl and silyl conjugate addition reactions (BCA and SCA, respectively), which proceed without the need for a transition-metal complex, represent reaction pathways that are distinct from those facilitated by transition-metal-containing species (e.g., Cu, Ni, Pt, Pd, or Rh based). The Lewis-base-catalyzed (NHC) transformations are valuable to chemical synthesis, as they can generate high enantioselectivities and possess unique chemoselectivity profiles. Here, the results of investigations that elucidate the principal features of the NHC-catalyzed BCA and SCA processes are detailed. Spectroscopic evidence is provided illustrating why the presen

SUBMITTER: Wu H 

PROVIDER: S-EPMC5549446 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature