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Formal [3 + 1 + 2] Cyclization/Cyclopropanation Cascade: A Modular Approach to Cyclopropane-Fused
Siyang Xing1, Xiqing Wang1, Lvrong Jin1
1Tianjin Key Laboratory of Structure and Performance for Functional Molecules; College of Chemistry, Tianjin Normal University, Tianjin300387, People's Republic of China.
Abstract:
A cascade strategy has been established for the efficient assembly of cyclopropane-fused dihydro-α-carbolines through the formation of four chemical bonds and two fused ring systems. Mechanistically, this transformation proceeds via sequential C-N coupling, double Michael addition, intramolecular cyclopropanation, and sulfonyl group elimination. This protocol showcases broad substrate scope and excellent synthetic modularity. Interestingly, cyclopropane-fused dihydro-α-carboline products could be further converted into indole-fused seven-membered azacycles via acid-promoted ring-opening reaction.
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