Stereoselective anti-SN2′ Mitsunobu reaction of α-hydroxy-α-alkenylsilanes
摘要:
A novel silyl group-directed anti-S(N)2' reaction of allylic alcohols under Mitsunobu reaction conditions is described. The Mitsunobu reaction of alpha-hydroxy-alpha-alkenylsilanes with a TBS or TIPS group gave the anti-S(N)2' product, in which regio- and stereochemical outcomes of the reaction depended on the steric bulkiness of the silyl group. (C) 2010 Elsevier Ltd. All rights reserved.
Enantioselective Synthesis of Siloxyallenes from Alkynoylsilanes by Reduction and a Brook Rearrangement and Their Subsequent Trapping in a [4+2] Cycloaddition
Two flavors of selectivity: An enantioselective Meerwein–Ponndorf–Verley‐type reduction of alkynoylsilanes by a chiral lithium amide followed by a Brookrearrangement and SE2′ electrophilic substitution provides the title compounds in a one‐pot process. In the case of enynoylsilanes, the generated vinylallenes undergo in situ [4+2] cycloaddition to afford highly functionalized polycyclic compounds
两种选择性:通过手性锂酰胺的对映选择性Meerwein-Ponndorf-Verley型还原炔基硅烷,然后进行Brook重排和S E 2'亲电取代,可在一锅法中得到标题化合物。在烯丙基硅烷的情况下,生成的乙烯基亚烷基会进行原位[4 + 2]环加成反应,以提供具有非常规的面部选择性的高度官能化的多环化合物。