An Asymmetric [3 + 2] Cycloaddition of Alkynes with Oxiranes by Selective C—C Bond Cleavage of Epoxides: Highly Efficient Synthesis of Chiral Furan Derivatives.

An efficient enantioselective [3+2] cycloaddition of alkynes with oxiranes via selective C–C bond cleavage of epoxides was developed. A number of optically active 2,5-dihydrofurans were obtained in excellent yields (up to 99%) and enantioselectivities (up to 95% ee) under mild reaction conditions. Moreover, chiral tetrahydrofuran could also be obtained by cycloaddition of alkene and oxirane or hydrogenation of chiral 2,5-dihydrofuran.