Formal [7 + 2] Cycloaddition of Arynes with N-Vinyl-α,β-Unsaturated Nitrones: Synthesis of Benzoxazonines and Their
Xiao-Pan Ma1, Liang-Gui Li1, Hong-Ping Zhao1
1State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China; School of Chemistry and Pharmaceutical Sciences , Guangxi Normal University , 15 Yu Cai Road , Guilin , 541004 , China.
Abstract:
Various benzoxazonines were synthesized through a formal [7 + 2] cycloaddition of arynes with N-vinyl-α,β-unsaturated nitrones under mild conditions. Controllable N-O bond cleavage of benzoxazonines afforded polysubstituted pyrrole-tethered benzopyrans and acyclic ketone-substituted phenols in moderate to good yields. Further transformations provided a facile approach to access useful building blocks with specific stereoselectivity.
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