Highly Selective Reduction of Acyclic β-Alkoxy Ketones to Protected syn-1,3-Diols
摘要:
The conversion of 1-(2-methoxyethoxy)ethyl-protected beta-hydroxy ketones to syn-1,3-ethylidene acetals is effected by Et3SiH and SnCl4. This reaction is proposed to proceed via a cyclic oxocarbenium ion intermediate and provides the products in yields that range from 69 to 94% and with diastereoselectivities that are >200:1.