A convenient one-step synthesis of gem-monofluoroalkylolefins starting from aldehydes or ketones was developed. This method comprises the utilisation of 2-(1-fluoroethyl)sulfonyl-1,3-benzothiazole according to Julia's procedure and opens a new opportunity for the synthesis of fluoroalkylidene derivatives. (C) 2003 Elsevier Ltd. All rights reserved.