Palladium-catalyzed enantioselective multiple carbonylation of 1-olefins. Synthesis of optically active 2-oxo-pentanedioates and butanedioates

In the presence of an oxidant such as 1,4-benzoquinone, cationic palladium( II) complexes catalyze a multiple carbonylation of 1-olefins to 2-oxopentan edioates and to butanedioates. The selectivity to 2-oxopentanedioates is re asonable only for styrene as the substrate and increases by increasing the carbon monoxide pressure. The triple carbonylation is regiospecific for sty rene, whereas the two possible regioisomers are formed for the aliphatic ol efins. The results of regioselectivity and enantioselectivity are interpret ed on the basis of common reaction intermediates for the two multiple carbo nylation processes. (C) 2000 Elsevier Science S.A. All rights reserved.