gem-Dibromomethyl Aromatics: Efficient Aldehyde Equivalents in the Knoevenagel-Doebner Reaction

A valuable variation of the Knoevenagel-Doehner reaction for the efficient synthesis of cinnamic esters is described. This reaction provides cinnamic esters in a single step from gem-dibromomethyl aromatics, which otherwise require the hydrolytic conversion of gem-dibromides into aldehydes, and demonstrates file use of an alternative reagent for noncommercial and expensive aldehydes. Further, the reaction of gem-dibromomethyl aromatics with malonic acid and di-tert-butyl dicarbonate for the one-pot synthesis of tert-butyl cinnamates is also described.