Diastereoselective Synthesis of trans‐2,3‐Diaryl(heteroaryl)‐3,6‐dihydropyrans by an Allylboration/Ring‐Closing‐Metathesis Sequence

Abstract

trans‐2,3‐Diaryl(heteroaryl)‐dihydropyrans were synthesized by an allylboration/ring‐closing‐metathesis sequence, using allylboranes formed in situ from the corresponding allylic alcohols. Aryl(heteroaryl) substituents were thus installed diastereoselectively onto dihydropyran rings in a trans fashion. These disubstituted dihydropyrans were further transformed into monosaccharide‐like tetrahydropyrans.