Synthesis of 1,1-Disubstituted Ethenes by Means of Sequential Cross-Coupling Reactions
作者:V. Fiandanese、G. Marchese、F. Naso、L. Ronzini
DOI:10.1055/s-1987-28164
日期:——
A variety of 1-alkenes are synthesized in 63-91% yields by means of sequential cross-coupling reactions of Grignard reagents with readily available or commercial starting materials, in the presence of transition-metal catalysts.
Direct preparation of substituted olefins from epoxides utilizing lithium tetraalkylcerate
作者:Yutaka Ukaji、Tamotsu Fujisawa
DOI:10.1016/s0040-4039(00)80709-1
日期:1988.1
Alkylated olefins were directly synthesized in good yields by the deoxygenation reaction of epoxides with concomitant introduction of the alkyl group using lithium tetraalkylcerate. Styreneoxide and (1-naphthyl)ethyleneoxide gave terminal olefins, while ethyleneoxide replaced by aliphatic substituent, 1,2-epoxy-4-phenyl butane, afforded internal olefin. The utility of the present method was demonstrated
Selective mono- and polymethylene homologations of copper reagents using (iodomethyl)zinc iodide
作者:AchyuthaRao Sidduri、Michael J. Rozema、Paul Knochel
DOI:10.1021/jo00062a010
日期:1993.5
A wide range of unsaturated aryl-, alkenyl-, alkynylcopper compounds can be selectively homologated by a methylene unit using (iodomethyl)zinc iodide or bis(iodomethyl)zinc. These reactions allow the generation of mixed allylic zinc-copper compounds which can be efficiently trapped with carbonyl compounds. An application to a general preparation of functionalized alpha-methylene-gamma-butyrolactones is described. The homologation of alkynylcoppers with (iodomethyl)zinc iodide allows a one-pot preparation of propargylic copper reagents which in the presence of a carbonyl compound provide various homopropargylic alcohols in excellent yields. In the absence of an electrophile, a clean quadruple methylene homologation of alkynylcoppers occurs to furnish dienic copper reagents. The homologation of other types of copper reagents is also possible, and carbanions at the alpha-position to amines as well as homoenolates of aldehydes or ketones can also be prepared by this method.
FIANDANESE, V.;MARCHESE, G.;NASO, F.;RONZINI, L., SYNTHESIS,(1987) N 11, 1034-1036
作者:FIANDANESE, V.、MARCHESE, G.、NASO, F.、RONZINI, L.