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In the presence of [Ni(dppp)Cl2] as a catalyst, vic-bromotrimethylsiloxyalkenes (1)couple with Grignard reagents to produce alkylated and arylated silyl enol ethers, or, after acid hydrolysis, the corresponding α-alkylated and α-arylated carbonyl compounds. In these reactions, 1 can be regarded as an enolonium equivalent.

Various types of mixed heteroatene oligomers can be readily prepared from heteroarene dihalides via stepwise coupling with heteroaryl Grignard reagents catalysed by a palladium–phosphine complex.

It has been established that dihalodiphosphinenickel(II) complexes exhibit extremely high catalytic activity for selective cross-coupling of Grignard reagents with aryl and alkenyl halides. This catalytic reaction can be employed in synthetic practice for reasons of simple procedures, mild reaction conditions, high yields and high purity of the coupling products, and the wide applicability to reactions involving primary and secondary alkyl (regardless of the presence or absence of β-hydrogen (s)), aryl, and alkenyl Grignard reagents and nonfused, fused, and substituted aromatic halides and haloolefins. Limitations lie in sluggish reactions between alkyl Grignard reagents and dihaloethylenes. The most effective catalysts are [Ni{(C6H5)2P(CH2)3P(C6H5)2}Cl2] for alkyl and simple aryl Grignard reagents, [Ni{(CH3)2P(CH2)2P(CH3)2}Cl2] for alkenyl and allylic Grignard reagents and [Ni{P(C6H5)3}2-Cl2] for sterically hindered aryl Grignard reagents and halides. Great stabilizing effects of phosphine ligands on the...

β-Bromovinyl ethyl ether smoothly couples with Grignard reagents in the presence of [Ni(dppp)Cl2] as a catalyst to give the corresponding alkylated and arylated vinyl ethers in good yields. This reaction provides a new one-step, functionalized two-carbon homologation of Grignard reagents.

Functionalized carbon chain elongation has been a central concern in transition-metal complex catalyzed carbon-carbon bond-forming reactions. As part of their continued studies on the palladium-phosphine complex catalyzed selective monoalkylation of organic polyhalides, they report here the first success in the regio- and stereoselective monoalkylation and -arylation of 1,1-dichloro-1-alkenes by Grignard or organozinc reagents in the presence of (PdCl/sub 2/(dppb)), dppb = Ph/sub 2/P(CH/sub 2/)/sub 4/PPh/sub 2/, as a catalyst to produce 1-substituted (Z)-1-chloro-1-alkenes.

β-Bromovinyl ethyl ether smoothly couples with Grignard reagents in the presence of [Ni(dppp)Cl2] as a catalyst to give the corresponding alkylated and arylated vinyl ethers in good yields. This reaction provides a new one-step, functionalized two-carbon homologation of Grignard reagents.

Platinum-catalyzed intramolecular hydrosilation of hydrodimethylsilyl ethers of homopropargyl alcohols proceeds regioselectively in a 5- exo - dig mode. The resulting vinylsilanes can be transformed into 3-alkanon-1-ol and 3-bromo-3-alken-1-ol derivatives by H 2 O 2 oxidation and bromine cleavage, respectively.

Various types of mixed heteroatene oligomers can be readily prepared from heteroarene dihalides via stepwise coupling with heteroaryl Grignard reagents catalysed by a palladium–phosphine complex.

A violet complex, possibly [trans-α,α′-bis-(trichlorosilyl)stilbene]bipyridylnickel(0), was obtained from the reaction of bis(trichlorosilyl)bipyridylnickel(II) with diphenylacetylene, and converted into trans-α,α′-bis(trimethylsilyl)stilbene by methylation.