Organocatalyzed Dearomative Cycloaddition of 2-Nitrobenzofurans and Isatin-Derived Morita–Baylis–Hillman Carbonates: Highly Stereoselective Construction of Cyclopenta[b]benzofuran Scaffolds

• DOI: 10.1021/acs.orglett.8b03786
• Publication Date: 2019-01-14T12:48:37Z
• Authors: Jian-Qiang Zhao; Lei Yang; Xiao-Jian Zhou; Yong You; Zhen-Hua Wang; Ming-Qiang Zhou; Xiao-Mei Zhang; Xiao-Ying Xu; Wei-Cheng Yuan
• Keywords: Isatin; Benzofuran

The first organocatalyzed asymmetric dearomative cycloaddition between 2-nitrobenzofurans and isatin-derived Morita-Baylis-Hillman carbonates has been developed. Using a modified cinchona alkaloid as the catalyst, series of structurally diverse cyclopenta[ b]benzofuran derivatives with three contiguous stereocenters, including spiro-quaternary chiral center, could be smoothly obtained in excellent results (all cases >20:1 dr, up to 99% yield 98% ee). utility this method was showcased by versatile transformations product.