H. Laurentrobert et al., ENHANCEMENT OF DIENOPHILIC AND ENOPHILIC REACTIVITY OF THE GLYOXYLIC-ACID BY BISMUTH(III) TRIFLATE IN THE PRESENCE OF WATER, Synlett, (10), 1998, pp. 1138
Bismuth(III) trifluoromethanesulfonate (1) is found to efficiently cat
alyze carbonyl-Diels-Alder or carbonyl-ene reactions between glyoxylic
acid and classical dienes or substituted olefins, in the presence of
water.