Scandium-catalyzed regio- and stereospecific methylalumination of silyloxy/alkoxy-substituted alkynes and alkenes.

Various alkynes and alkenes having a tethered ether group undergo methylalumination reactions with unprecedented regio- and stereoselectivity in the presence of a cationic half-sandwich alkylscandium species as a catalyst. The oxygen atom of the ether group plays an important role in controlling the selectivity, possibly by coordinating to the metal center. Even when a bulky tert-butyl(diphenyl)silyloxy group is used as the tether group, there is no loss of selectivity.