文摘
The effectiveness of Sc(OTf)3 as a Lewis acid catalyst for the 1,4-addition reaction of carbamates to appropriate 2-acetyl-2-pentenoic esters is herein reported. In particular, N-benzyl-(tert-butyldimethylsilyloxy)carbamate added efficiently to the title substrates to afford a new class of polyfunctionalized isoxazolidines and isoxazolines.