Radical Cyclizations of Cyclic Ene Sulfonamides Occur with β-Elimination of Sulfonyl Radicals to Form Polycyclic Imines
作者:Hanmo Zhang、E. Ben Hay、Steven J. Geib、Dennis P. Curran
DOI:10.1021/ja408387d
日期:2013.11.6
Radical cyclizations of cyclic ene sulfonamides provide stable bicyclic and tricyclic aldimines and ketimines in good yields. Depending on the structure of the precursor, the cyclizations occur to provide fused and spirocyclic imines with five-, six-, and seven-membered rings. The initial radical cyclization produces an α-sulfonamidoyl radical that undergoes elimination to form the imine and a phenylsulfonyl
环烯磺酰胺的自由基环化以良好的产率提供稳定的双环和三环醛亚胺和酮亚胺。根据前体的结构,发生环化以提供具有五元环、六元环和七元环的稠合亚胺和螺环亚胺。最初的自由基环化产生α-磺酰胺酰基自由基,该自由基经过消除形成亚胺和苯磺酰基自由基。在相关方法中,3,4-二氢喹啉也可以通过N-(2-碘苯磺酰基)四氢异喹啉的自由基易位反应来制备。无论哪种情况,非常稳定的磺酰胺在温和的还原条件下都会裂解形成亚胺(而不是胺)。