Work

Bi(OTf)3-, TfOH-, and TMSOTf-Mediated, One-Pot Epoxide Rearrangement, Addition, and Intramolecular Silyl-Modified Sakurai (ISMS) Cascade toward Dihydropyrans: Comparison of Catalysts and Role of Bi(OTf)3

Year: 2011

Type: article

Abstract: Catalytic quantities of bismuth(III) triflate efficiently initiate the rearrangement of epoxides to aldehydes, which subsequently react with (Z)-δ-hydroxyalkenylsilanes to afford 2,6-disubstituted 3,6-dihydro-2H-pyrans. Isolated yields of desired products using Bi(OTf)(3) were compared with yields obtained when the reactions were run with TfOH and TMSOTf in the presence and absence of several additives. These studies, as well as NMR spectroscopic analyses, indicate an initial Lewis acid/base interaction between Bi(OTf)(3) and substrates providing TfOH in situ.

Source: The Journal of Organic Chemistry

DOI: 10.1021/jo201478d