Reversal of aldehyde diastereofacial selectivity in a methyl ketone aldol reaction. Application to the synthesis of the calyculin spiroketal
作者:David A. Evans、James R. Gage
DOI:10.1016/s0040-4039(00)97005-9
日期:1990.1
It has been observed that aldehyde diastereofacialselectivity in a methyl ketone aldol reaction can be fully regulated under appropriate conditions. Addition of the lithium enolate provided the product derived from apparent chelation control, while Lewis acid-promoted addition of the derived silyl enolether afforded the Felkin-Anh diastereomer. Application of this methodology to the ongoing synthesis