Anionic [3,3]-sigmatropic rearrangement of N-phenyl-O-acylhydroxylamines to o-aminophenylcetic acids.
作者:Yasuyuki Endo、Shoji Hizatate、Koichi Shudo
DOI:10.1016/0040-4039(91)85091-i
日期:1991.6
N-Phenyl-O-acylhydroxylamines rearrange under basic conditions to afford o-aminophenylacetic acids. The rearrangement can be rationalized in terms of [3,3]-sigmatropicshifts of an enolized N-phenyl-O-acylhydroxyl-amine.
An unprecedented direct C H bond functionalization of unprotected phenols with alpha-aryl alpha-diazoacetates and diazooxindoles was developed. A tris(2,4-di-tert-butylphenyl) phosphite derived gold complex promoted the highly chemoselective and site-selective C H bond functionalization of phenols and N-acylanilines with gold-carbene generated from the decomposition of diazo compounds, furnishing the corresponding products in moderate to excellent yields at rt. The salient features of this reaction include readily available starting materials, unprecedented C H functionalization rather than X H insertion, good substrate scope, mild conditions, high efficiency, and ease in further transformation. To the best of our knowledge, this is the first example of C H functionalization of unprotected phenols with diazo compounds.