Organometallics of Organic Active Intermediates

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Pronucleophiles (H-Nu) add to the carbon-carbon double bond of allenes in the presence of a palladium catalyst to give the corresponding olefins in good to high yields (hydrocarbonation reaction). The regiochemistry of the addition depends upon the substituent of allenes ; dialkyl, aryl, and monoalkylallenes give the terminal (g) adducts, arylallenes bearing an electron withdrawing group at the para-position of aromatic group produce the internal (beta) adducts, and alkoxy (or phenoxy) allenes afford the a-adducts. The palladium catalyzed addition of H-Nu to sulfur substituted allenes, allenylsulphides, gives the g-addition products in good to high yields. This regioselectivity is in marked contrast with that of the oxygen substituted allenes.Although Wurtz coupling reaction of 9,10-dichloro-9,10-dimethyl-9,10-disilaanthracene with sodium in toluene at 110 ﾟC formed bridged dimer in only 7 % yield, the increased yields of the dimer have been achieved by direct reaction of 9,10-dihydro-9,10-dimethyl-9,10-disilaanthracene with lithium.Thermolysis of o- (3-trifuluoroacetyloxy-1-propenyl) benzyltributylstannane at 80 ﾟC gave a-vinyl-o-quinodimethane, which reacted with dienophiles to afford Diels-Alder adducts with two stereoisomers in good yield.First synthesis, X-ray structure analysis and reaction of alkenyltriphenylbismuthonium salts were studied.Organotellurium compounds readily undergo Te-Li exchange to give a variety of organolithium compounds which include highly reactive and unstable reagents such as acyl-, aroyl-, and carbamoyl-lithiums.The selective preparation of unsymmetrical ketones and a-diketones was accomplished by the reaction of decacarbonyldimanganese (Mn2 (CO) 10) with two kinds of alkyllithiums.