Boron trifluoride–tetrahydrofuran complex: a superior trigger for the Yamaguchi–Hirao alkylation of lithio-acetylides by epoxides

Use of BF3·THF complex in place of the usual BF3·OEt2 analogue in the Yamaguchi–Hirao alkylation of lithio-acetylides 2 by monosubstituted epoxides 3 gives consistently superior isolated yields (ca. 90%) of homopropargylic alcohols 1.