Formation of functionalized cyclopentenes via catalytic asymmetric [3+2] cycloaddition of acrylamides with an allenoate promoted by dipeptide-derived phosphines

Abstract

Acrylamides derived from 3,5-dimethyl-1H-pyrazole are employed in the asymmetric [3+2] cycloaddition with the allenoate, tert-butyl buta-2,3-dienoate, for the first time. d-Threonine-l-tert-leucine-based bifucntional phosphines are effective catalysts for the above reactions, affording regiospecific [3+2]-annulation products in excellent yields and with moderate enantioselectivities. © Georg Thieme Verlag Stuttgart - New York.