Diastereoselective bromine/lithium exchange reactions of 3-alkoxy-1,1-dibromo-alkanes
作者:Reinhard W. Hoffmann、Hans-Christian Stiasny、Jochen Krüger
DOI:10.1016/0040-4020(96)00260-8
日期:1996.5
The diastereoselectivity in the bromine/lithium exchange reaction on chiral 3-alkoxy-1,1-dibromo-alkanes has been investigated. The differentiation of the two diastereotopic bromine atoms was found not to depend solely on a conformational preorganisation of the substrate, as surmised previously. It became apparent that steric crowding at the δ-center controls the spatial orientation of a C-3-oxygen
研究了手性3-烷氧基-1,1-二溴代烷烃在溴/锂交换反应中的非对映选择性。如先前所推测的,发现两个非对映体溴原子的分化不仅仅取决于底物的构象预组织。显然,在δ中心的空间拥挤控制了在手性中心的C-3-氧取代基的空间取向,这可能是观察到的不对称诱导的原因。