HBF4·OEt2 as a versatile reagent for the Hosomi–Sakurai allylation and Prins cyclization: one-pot synthesis of symmetrical 4-fluorotetrahydropyrans

The synthesis of symmetrical 2,6-disubstituted 4-fluorotetrahydropyran derivatives has been achieved using HBF4·OEt2 via a tandem allylation and Prins cyclization. This is a highly efficient and diastereoselective approach for the preparation of 4-fluorotetrahydropyrans in a single step. The use of readily available and easy to handle reagent HBF4·OEt2 makes this method simple, convenient and practical.