Ambient temperature method for the generation and Diels–Alder trapping of benzofuran-2,3-quinodimethane (2,3-dimethylidene-2,3-dihydrobenzofuran)

Abstract

The Ito–Saegusa method has been used to generate benzofuran-2,3-quinodimethane 10 from the corresponding sily acetate 17b in solution at –4 °C. The intermediate reacts efficiently with a range of reactive Diels–Alder dienophiles with moderate to good levels of regioselection; the structure of the major diastereoisomer has been determined by X-ray analysis.