Silicon hydrides in organic synthesis

Abstract

In the past few years we have developed an array of composite reducing systems based on combinations of tin or silicon hydrides with various transition-metal homogeneous catalysts such as palladium(O), ruthenium(II) and molybdenum(O) complexes. These represent a useful family of reducing media that effect highly selective reductions of various organic functional groups, such as allylic heterosubstituents, α,β-unsaturated carbonyl compounds and α-halo ketones. More recently, we have discovered that diiodosilane (DIS), which has never been used previously in organic synthesis, transforms a broad variety of useful functional-groups under mild conditions. This new reagent was found to exhibit properties and reactivities that are, in some cases, either superior or complementary to those of the well-known iodotrimethylsilane. In addition to its ability to cleave ethers, alcohols, ketals, acetals, α-haloketones, etc., this new reagent may also serve as a unique- reducing agent. As a multipurpose reagent, DIS allows sequential cleavage, reduction and iodination of oxygen functionalities, all of which are carried out by a single reagent. © 1989 IUPAC