Esters and N,N-dialkylamides of 2-(trifluoromethyl)acrylic acid (TFMAA) through Pd-catalysed carbonylation of fluorinated unsaturated substrates

Esters and amides of 2-(trifluoromethyl)acrylic acid (TFMAA) have been synt hesised by two different routes involving GO-chemistry. The alkoxycarbonyla tion of 2-bromo-3,3,3-trifluoropropene was carried out in the presence of P dCl2(PPh3)(2). High substrate conversions were obtained, but the yield in a crylic esters was generally low because the desired unsaturated esters reac ted further adding a molecule of alcohol to the C-C double bond. The carbon ylation of 2-bromo-3,3,3-trifluoropropene in the presence of secondary amin es produced the corresponding unsaturated amides in high yields; the additi on of the amine to the C-C double bond also occurred, but this side reactio n was minimised by using secondary cyclic amines such as morpholine or pipe ridine. Alternatively, the acrylic esters can be obtained by hydromethoxyca rbonylation of 3,3,3-trifluoropropyne using the catalytic system Pd(OCOCH3) (2)/2-pyridyldiphenylphosphine/CH3SO3H. In this process the most important side product is the isomeric crotonic ester. The regioselectivity of the re action can be controlled to a great extent by a suitable choice of the solv ent. (C) 1999 Elsevier Science B.V. All rights reserved.