Direct synthesis of tetrahydropyran-4-ones via O 3 ReOH-catalyzed Prins cyclization of 3-chlorohomoallylic alcohols.

A new variation of Prins cyclization to directly and stereoselectively synthesize cis -2,6-disubstituted tetrahydropyran-4-ones from 3-chlorohomoallylic alcohols and aldehydes catalyzed by perrhenic acid is reported. The reaction is generally compatible with a range of aliphatic and aromatic aldehydes and 24 examples of tetrahydropyran-4-one products have been prepared in moderate to good yields. This methodology highlights the use of simple starting materials and commercially available aqueous perrhenic acid as a catalyst for Prins cyclization reactions to directly synthesize 2,6-disubstituted tetrahydropyran-4-ones.