1,3-Dipolar cycloadditions of alkynyl Fischer carbene complexes with nitrones
Abstract
Phenylethynyl Fischer carbene complexes of chromium 1 and tungsten 2 were found to undergo chemoselective, regioselective and rate-enhanced 1,3-dipolar cycloadditions with phenyl N-t-butyl nitrone 3 at room temp. to give 2,3-dihydroisoxazole carbene complexes 4 and 5 in excellent yields.