Host: Division of Organic Chemistry, The Pharmaceutical Society of Japan
We have developed a highly effective secondary benzylation system for aromatic nucleophiles using benzyl alcohols catalyzed by rare-earth metal and hafnium triflate in nitromethane. The benzylation proceeds smoothly even in the presence of water. In this presentation, we will report a convenient method for α-secondary benzylation of enolacetates as a nucleophile. Various enol acetates prepared from methyl or cyclic ketone underwent sec-benzylation with sec-bezyl alcohols in the presence of 0.5-1 mol% of La, Yb, Sc, and Hf triflates. Addition of Mg(ClO4)2 increased the yield of the benzylation. Various 1-phenylethanols bearing a functional group (e.g, hydroxy, acetoxy, benzyloxy, tert-butyldimethylsilyloxy) were able to be used for the benzylation.
