American Chemical Society
jo9b02590_si_003.cif (13.49 kB)

Ortho-Hydroxylative ipso-Cyclization of N‑arylpropiolamide

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posted on 2019-12-17, 12:37 authored by Yu-Chao Wang, Jin-Biao Liu, Hongwei Zhou, Wenlin Xie, Pornchai Rojsitthisak, Guanyinsheng Qiu
A facile protocol for the tunable synthesis of 10-hydroxy-1-azaspiro[4.5]­deca-3,6,8-trien-2-ones and benzo­[b]­pyrrolo­[2,1-c]­[1,4]­oxazin-3-ones is described. A tunable synthesis has been realized by the use of ZnBr2/oxone and tetra-n-butylammonium bromide (TBAB)/oxone. The reaction proceeds smoothly with high efficiency and a broad substrate scope. Mechanistic studies indicate that an N-protecting group-assisted ortho-trapping reaction is involved. In the transformation, the reaction undergoes α-addition, ipso-cyclization, and ortho-trapping of the resulting spirocyclic species.