Indium-Catalyzed Reductive Molecular Transformations Using Hydrosilanes

Abstract

Reductive molecular transformations by indium/hydrosilane catalyst systems are described herein. A catalytic reductive molecular transformation using a hydrosilane is an important synthetic tool, because silicon-based reducing reagents are frequently easy to handle and exhibit high chemoselectivity to each functional group, due to their lower reactivity than that of other reducing agents. In order for a hydrosilane to show the potential ability as a valuable reducing agent in organic synthesis, therefore, the appropriate choice of a catalyst is an imperative and a significant matter. We continue to perform the use of indium catalysts as good promoters for a variety of silane-mediated reductive transformations. In this review, we summarized our recent results for indium-catalyzed or-mediated transformations as the following chapters: (i) simple reductions of functional groups, especially for carboxylic acid derivatives; (ii) reductive alkylations at oxygen-, nitrogen-, halogen-, carbon-, and sulfur-atoms, by using carboxylic acids as alkylation reagents; (iii) applied reactions based on the reductive transformations including cyclization and hydroamination; (iv) other type reactions promoted by indium (III) compounds, such as Knoevenagel condensation and oxidative coupling through Oppenauer oxidation.