Synthesis of 2,3-Disubstituted Dihydrobenzofurans from o-Quinone Methides and Sulfur Ylides

A facile and efficient approach to dihydrobenzofurans from sulfur ylides and o-quinone methides (o-QMs) was developed.In most cases, the reaction could be completed in the presence of N,N-diisopropylethylamine (DIPEA) in CH2Cl2 at room temperature within 1 h, providing trans-2,3-disubstitiuted dihydrobenzofurans in good to excellent yields.The reaction could expand to a scale of grams, and the products could be converted into the potentially bioactive benzofuran derivatives.The plausible mechanism is proposed.