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.