Sr. Angle et al., FORMATION OF CARBON-CARBON BONDS VIA QUINONE METHIDE-INITIATED CYCLIZATION REACTIONS, Journal of organic chemistry, 59(21), 1994, pp. 6322-6337
p-Quinone methides were found to be excellent electrophilic cyclizatio
n initiators for the formation of six-membered rings. Cyclizations to
form five- and seven-membered rings were also studied. Oxidation of 2,
6-disubstituted phenols with Ag2O afforded the corresponding quinone m
ethides. A wide range of cyclization terminators/nucleophiles were fou
nd to be effective in the cyclizations, including: allylsilane, beta-k
eto esters, furan, pyrrole, indole, and a number of alkenes. The yield
s of the cyclizations were generally high.