Quinone methide intermediates in organic photochemistry*
Peter Wan**, Darryl W. Brousmiche, Christy Z. Chen, John Cole, Matthew
Lukeman, and Musheng Xu
Department of Chemistry, Box 3065, University of Victoria,
Victoria, British Columbia, V8W 3V6, Canada
Abstract: Quinone methides are widely encountered reactive intermediates
in the chemistry of phenols and related compounds. This paper summarizes
our recent progress in uncovering new and general photochemical methods
for forming quinone methides of various structural types in aqueous
solution. Their mechanism of formation and subsequent chemistry are
also discussed. New examples of excited-state intramolecular proton
transfer (ESIPT) have been uncovered in these studies. We have also
discovered that appropriately designed biphenyls and terphenyls display
photochemistry that is best rationalized by highly polarized and planar
excited states of these ring systems, which can efficiently lead to
the corresponding extended quinone methides.
*Lecture presented at the XVIIIth IUPAC Symposium on
Photochemistry, Dresden, German , 22-27 July 2000.Other presentations
are published in this issue, pp.395-548.
**Corresponding author