Biomimetic Cycloaddition Approach to Tropolone Natural Products via a Tropolone Ortho-quinone Methide
作者:Robert M. Adlington、Jack E. Baldwin、Alexander V. W. Mayweg、Gareth J. Pritchard
DOI:10.1021/ol026467r
日期:2002.8.1
toward a possible biomimetic hetero Diels-Alder reaction is reported between humulene and a novel tropolone ortho-quinone methide. A suitable tropolone ortho-quinone methideprecursor has been prepared from 3-methyl-2-furoate. Heating the ortho-quinone methideprecursor gave a tropolone ortho-quinone methide, which in the presence of humulene underwent a hetero Diels-Alder reaction to give a deoxy analogue
Expedient synthesis of a highly substituted tropolone via a 3-oxidopyrylium [5+2] cycloaddition reaction
作者:Jack E. Baldwin、Alexander V.W. Mayweg、Gareth J. Pritchard、Robert M. Adlington
DOI:10.1016/s0040-4039(03)00987-0
日期:2003.6
An expedient ten-step synthesis of a substituted tropolone is described. The synthesis involves a 3-oxidopyrylium [5+2] cycloaddition reaction with acrylonitrile as the key step, affording a highly functionalized [3.2.1]-bicycle 10 as a single regioisomer. The nitrile substituent of the reduced cycloadduct 12 permits efficient ether-bridge cleavage and tropolone 15 is obtained after a final bis-oxidation