Synthesis of 2-substituted tetrahydrofurans

Abstract

We have developed a three-stage scheme for the preparative synthesis of 2-substituted tetrahydrofurans from allyl halides and aldehydes to give the first stage — a Grignard reaction — mixed alkoxides, which on treatment with acetic anhydride are converted to 4-acetoxy-1-alkenes. Addition of hydrogen bromide to the latter contrary to Markownikoff's rule gives 4-acetoxy-1-bromoalkanes, which as a result of hydrolysis form 2-R-tetrahydrofurans.