Stereocontrolled Route to 2,3,5-Trisubstituted Tetrahydrofurans. Intermediates for the Total Synthesis of Polyether Antibiotics.

Article abstract of DOI:10.1021/jo00389a600

The stereoselective synthesis of diastereomers of 2,3,5-trisubstituted tetrahydrofurans has been accomplished by Lewis acid catalyzed acetal rearrangement.The reaction sequence starts with 4,7-dihydro-1,3-dioxepins 4, which are isomerized to 4,5-dihydro-1,3-dioxepins 6.The key step of the procedure is the stereocontrolled rearrangement of these mixed alkyl vinyl acetals 6, followed by reduction. 2,3,5-Trisubstituted tetrahydrofurans are of general interest for the synthesis of polyether antibiotics.