A pineno-salen type catalyst for the enantioselective Nozaki–Hiyama–Kishi reaction
摘要:
A new class of pineno-salen type ligands 10, 11, 17, 20, 23, and 24 has been developed. The catalyst formed from chromium(II)-10 promotes the enantioselective Nozaki-Hiyama-Kishi allylation of alkyl and aryl aldehydes using allyl bromide. Notably, the asymmetric addition of vinyl halide to benzaldehyde was achieved with 24% ee. (C) 2012 Elsevier Ltd. All rights reserved.
A new class of chiral spirocyclic borate ligands 5a–d with a rigid borocycle has been developed. The catalyst formed from chromium(II)-5a promotes the highly efficient enantioselective Nozaki–Hiyama allylation of alkyl and aryl ketones using allyl bromide. The scope of the present method is shown to be wide, and it affords an efficient access to chiral tertiary homoallylic alcohols.