An Odyssey from Stoichiometric Carbotitanation of Alkynes to Zirconium-catalysed Enantioselective Carboalumination of Alkenes

摘要

It has recently been found that alkylalane-zirconocene reagent systems can react with alkynes and alkenes via at least three different paths, i.e., (ⅰ) straightforward carbometallation without involving C—H activation, (ⅱ) cyclic carbometallation via β C—H activation, and (ⅲ) hydrometallation. Various factors affecting the courses of such reactions have been delineated. In some cases, it is even possible to steer these reactions in the desired direction. Our recent development of a Zr-catalysed enantioselective alkene carboalumination reaction is an outgrowth of the above-mentioned systematic, exploratory, and mechanistic investigation.