M. Yanagisawa et al., Aldol reaction of enol esters catalyzed by cationic species paired with tetrakis(pentafluorophenyl)borate, CHEM PHARM, 48(11), 2000, pp. 1838-1840
The crossed aldol reaction of enol esters, which are weak carbon nucleophil
es, with aldehydes was effectively carried out under mild conditions by usi
ng a catalytic amount of several cationic species paired with tetrakis(pent
afluorophenyl)borate.