Stereospecific Synthesis of Tetrasubstituted Alkenes via Sc-Catalyzed Methylalumination

Significance

The paper described a regio- and stereospecific methylalumination of silyloxy and alkoxy alkynes and alkenes catalyzed by scandium complexes. The stereochemistry of the alkyne ­addition products is controlled by the substituent on the triple bond. Phenyl and alkyl groups facilitate a syn addition with methyl at the distal position of the ether moiety; the trimethylsilyl group ­facilitates an anti addition with methyl at the ­proximal position of the ether moiety.