Catalyst-free synthesis of 2,3-dihydrobenzofurans through [4+1] cycloaddition of ortho-hydroxyphenylsubstituted para-quinone methides and sulfur ylides

摘要

AbstractAn efficient [4+1] cycloaddition ofortho-hydroxyphenylsubstitutedpara-quinone methides and sulfur ylides was achieved under the catalyst-free condition. With this developed protocol, a series oftrans-2,3-dihydrobenzofurans were obtained in excellent yields (up to 99%) with high diastereoselectivities (>20:1 dr). The usefulness of the protocol was also demonstrated by the versatile conversions of the 2,3-dihydrobenzofurans into other functionalized benzofurans.Graphical abstractDisplay Omitted]]>