Malonic to Acetic Ester Transformation by Boric Acid

One of our synthetic projects involves a step of removing a carbalkoxy group from a substituted malonic ester. For accomplishing that goal, Krapcho's method¹ was deemed unsuitable, because the malonic ester contains an allylic halogen which is liable to attack by dimethyl sulfoxide (Kornblum reaction). Our recent work on using iodotrimethylsilane² to achieve decarbal-koxylation of such esters was partly impelled by that need; however, the prohibitive economics associated with even a medium-scale preparation forced us to develop a less expensive alternative.