Chiral Acylsilanes in Organic Synthesis. Diastereoselective 1,2‐Additions to Racemic Alkoxymethyl‐Substituted Acylsilanes

Abstract

Abstract The synthesis of the three alkoxymethyl‐substituted acyisilanes 1 – 3 is described ( Schemes 1 and 2 ). Their reactions with NaBH 4 as well as PhLi gave the corresponding alcohols with moderate to good diastereoisomeric induction (up to 78% de; see Table ), depending upon the solvent used ( Scheme 3 ). The results indicate that in Et 2 O, the reactions with PhLi proceed via 6‐membered chelates (see C in Scheme 4 ) leading to the products with high de's (74–78%). In THF, these chelates are not formed, and as a consequence, the additions take place with reversed and lower stereoselectivities (34–50% de).