Synthesis of 6H-dibenzo[b,d]pyran-6-ones via dienone-phenol rearrangements of spiro[2,5-cyclohexadiene-1,1′(3′H)-isobenzofuran]-3′-ones
作者:David J. Hart、Adrienne Kim、Ramanarayanan Krishnamurthy、Gregory H. Merriman、Anne-Marie Waltos
DOI:10.1016/s0040-4020(01)80487-7
日期:1992.1
A series of spiro[2,5-cyclohexadiene-1,1′(3′H)-isobenzofuran]-3′-ones were prepared from metalled benzamides and 4,4-dimethoxycyclohexadienone. Rearrangement of these spirodienones under a variety of conditions gave substituted 6H-dibenzo[b,d]pyran-6-ones. Rearrangements in aqueous sulfuric acid gave products of formal O-migration while rearrangements in trifluoroacetic anhydride-trifluoroacetic acid-sulfuric
PIFA-Mediated Dearomatizative Spirocyclization of Phenolic Biarylic Ketones via Oxidation and C–C Bond Cleavage
作者:Gui-Hua Zhao、Bi-Qing Li、Shuang-Shuang Wang、Man Liu、Yuan Chen、Bin Wang
DOI:10.1021/acs.joc.0c00971
日期:2020.7.17
The dearomatizing spirocyclization of phenolic biarylic ketones using PhI(OCOCF3)2 as oxidant is presented. The reaction affords various cyclohexadienones through C–Cbondcleavage under mild conditions. Mechanistic investigations reveal that an exocyclic enol ether acts as the key intermediate in the transformation.