Bismuth(III) Catalyzed Cyclic Ether Syntheses

BiBr3 and Bi(OTf)3 have proven to be effective catalysts for Mukaiyama aldol reactions and Intramolecular silyl-Modified Sakurai (ISMS)/silyl-Prins type reactions towards cis-2,6-disubstituted-3,4-dihydropyrans. Herein are described studies towards the use of these Bi(III) salts in multi-component reactions to afford cyclic ethers, a structural motif found in natural products, such as the diospongins, which have been reported to posses potential therapeutic value. These investigations have also attempted to shed light on the ambiguity surrounding the method of action behind Bi(III) salts\u27 catalytic power