Stereoselective indium-mediated allylation reactions

Since the discovery that indium could affect a Barbier-type allylation of carborryls in water over a decade ago, interest in the utility of indium metal and its salts to influence organic transformations has increased exponentially. Control of chemo-, regio-, and especially stereoselectivity in indium-mediated reactions has proven to be a challenge, however, examples of such discerning processes are now beginning to appear on a regular basis. Indium has been found to be effective in the allylation of carbonyls, carbo metallation of some alkenes and alkynes. It has also been shown to be a reducing agent for a variety of organic functional groups, mediators for a variety of coupling reactions, and more recently indium reagents have been utilized as initiators for radical transformations. This review presents an overview of the development of stereoselective indium-mediated organometallic reactions.