Catalytic applications of F8BINOL: asymmetric oxidation of sulfides to sulfoxides

The effect of fluorine substitution at the 5, 5′, 6, 6′, 7, 7′, 8 and 8′ positions of 2,2′-dihydroxy-1,1′-binaphthyl (BINOL) on its catalytic activity in titanium-mediated sulfide oxidation with tert-butyl hydrogen peroxide and cumyl hydrogen peroxide was examined. Introduction of fluorines into the BINOL scaffold was found to increase the electrophilic character of the Lewis acidic titanium center of the catalyst. Moreover, under otherwise identical conditions, BINOL and 5,5′,6,6′,7,7′,8,8′-octafluoro-2,2′-dihydroxy-1,1′-binaphthyl (F8BINOL) of the same absolute configuration led to opposite sense of chiral induction in the sulfoxidation process.