[(NHC)(PR 3 )PdX 2 ] complexes (NHC = N-heterocyclic carbene) are active precatalysts in the palladium-catalyzed allylation of carbonyl compounds with allylic acetates and diethylzinc. A comparative study examining the catalytic activity of a series of six of these complexes was carried out with allyl and cinnamyl acetates. [(IMesMe)(PPh 3 )PdI 2 ] was found to be the most versatile precatalyst (IMesMe = 1-mesityl-3-methylimidazol-2-ylidene) and the scope of the reaction was investigated with this complex. [(IMesMe)(PPh 3 )-PdI 2 ] catalyzes the allylation of aromatic (except 4-nitrobenzaldehyde) and aliphatic aldehydes (including enolizable aldehydes) with cinnamyl acetate to give the corresponding homoallylic alcohols in 57-98 % yields and diastereoselectivities ranging from 70:30 to 92:8. The allylation of acetone also takes place under the same conditions, leading to the expected adduct in 63 % yield. The reaction with cyclohexenyl acetate proceeds at room temperature to afford the homoallylic alcohols in 40-78 % yields with excellent diastereoselec-
Polyphenylalkene derivatives Q 0740Synthesis of Chiral Imino-and Amino-imidazolium Salts and of Chelating Amino-N-heterocyclic Carbene Palladium(II) Complexes. -Pure diastereomeric amino-imidazolium salts (4 examples) are prepared. The mixture of the silver(I) complex (I) derived therefrom and [PdCl(allyl)]2 catalyzes the allylic alkylation of acetate (II) with malonate to give the product with moderate yield and enantioselectivity. -(FLAHAUT, A.; BALTAZE, J.-P.; ROLAND*, S.; MANGENEY, P.; J. Organomet. Chem. 691 (2006) 16, 3498-3508; Lab. Chim. Org., CNRS, Univ. P. et M. Curie, F-75252 Paris, Fr.; Eng.) -Klein 48-108
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