Phosphine-catalyzed [3 + 2] cycloadditions of trifluoromethyl enynes/enediynes with allenoates: access to cyclopentenes containing a CF3-substituted quaternary carbon center

Abstract

Herein, the first use of trifluoromethyl-substituted enynes/enediynes as non-classical electron-deficient olefins for phosphine-catalyzed [3 + 2] cycloaddition with allenoates is reported. This reaction occurs with excellent regioselectivity under mild conditions, affording alkyne- and diyne-tethered cyclopentene derivatives containing a CF₃-substituted quaternary carbon center in moderate to good yields.