Asymmetric gamma-Methoxyallylation with the Robust 10-TMS-9-Borabicyclo[3.3.2]decanes

摘要

The asymmetric gamma-methoxyallylboration of aldehydes with the configurationally very stable 1 gives nonracemic threo-beta-methoxyhomoallylic alcohols 7 (65-93%) with excellent selectivity (96-99% de, 98-99% ee). The corresponding homoallylic amines 10 are obtained from N-H aldimines with similar efficiency (72-96%) and with excellent diastereoselectivity (98% de) but with lower enantioselectivity (56-86% ee). These new reagents provide ready access to a Taxol side chain derivative.