Palladium-catalysed cross-coupling reactions of triorganoindium reagents with alkenyl halides

The regio- and stereoselectivity of the palladium-catalysed cross-coupling reactions of indium organometallics with stereodefined 1-haloalkenes and 1,1-dihaloalkenes have been studied. Triorganoindium reagents (R3In; R = alkyl, alkenyl, aryl and alkynyl) can be stereospecifically coupled with stereodefined alkenyl iodides in good yields and short reaction times under palladium catalysis. Additionally, the palladium-catalysed cross-coupling reaction of R3In (90 mol-%) with 1,1-dibromo-1-alkenes gave dicoupling products in high yields. When the reaction was performed with 40 mol-% of aryl-, vinyl- and alkynylindium derivatives, trans-selective monosubstitution products were obtained in moderate to good yields. These selective couplings were performed with [Pd(2)dba(3)]/P(2-furyl)(3) (1:1, 2mol-%) at 0 degrees C or, for 1,1-dibromo-1-alkenes with an aromatic group in the beta-position, [Pd(DPEPhos)Cl-2] (2 mol-%) at room temperature as the catalytic system. The resulting (Z)-monobromoalkenes can be further functionalized by cross-coupling reaction with various R3In (R = alkyl, aryl and alkynyl) in the presence of [Pd(tBu(3)P)(2)] as catalyst, at room temperature, to provide trisubstituted olefins in good yields. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).