Photochemical reactions of several halo/aryl sulfide-substituted alkyl phenylglyoxylates (1) were studied. For 2'-bromo-(1b), 2'-iodo-(1c), 2'-(phenylthio)-(1d), and 2'-(phenylsulfinyl)- (1e) ethyl phenylglyoxylate, vinyl phenylglyoxylate (2), proposed to be the result of β-