Carbon-carbon bond formation and annulation reactions using trimethyl and triethyl orthoformates

Abstract

Synthetic utility of trimethyl and triethyl orthoformates for carbon-carbon bond formation is briefly surveyed, particularly in relation to dialkoxymethylation, carbonyl transposition-homologation, and cycloalkenone annulation reactions recently reported from the authors' and other laboratories. The complex mechanisms involved in the one-step and two-step annulations of rigid β ,γ - and γ , δ -unsaturated ketones have been discussed.