η¹‐(1<i>S</i>, 2<i>E</i>)‐1‐(<i>N,N</i>‐diisopropylcarbamoyloxy)‐3‐trimethylsilylallyllithium()‐Sparteine: Structure of a Chiral, Carbamoyloxy‐substituted Allyllithium Compound

Abstract

Configurationally stable lithium compounds such as 1, which are substituted by oxygen in the α-position, are useful reagents for the stereoselective synthesis of homoallyl alcohols. Solid-state structure and reactivity of 1 are in harmony: the preferred silylation at C1 and the steroselective reaction with aldehydes at C3 are understandable from the η1-coordination of the Li atom at the allyl unit. Furthermore, the unusually long C1O1 distance (147.6 pm) confirms earlier ab initio studies.