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Abstract:
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The bis(triphenylphosphine) nickel dichloride-catalyzed reaction of thiophenols and aryl sulfides with phenyl-magnesium and methylmagnesium bromides produced biphenyls and toluenes, respectively.
The coupling of p-t-butylthioanisole with ethylmagnesium bromide and cyclohexylmagnesium bromide in the presence of (1,3-diphenylphosphinopropane)nickel dichloride produced p-t-butylethylbenzene and p-t-butylcyclohexylbenzene, respectively, while the coupling with isopropylmagnesium bromide led to the formatin of n-propyl as well as isopropyl aryl derivatives. The same sulfide reacted with isopropylmagnesium and cyclohexylmagnesium bromides in the presence of anhydrous nickel dichloride and triphenylphosphine to produce t-butyl-benzene. With ethylmagnesium bromide t-butylbenzene and p-t-ethylbutylbenzene were produced.
p-t-Butylthiophenol afforded t-butylbenzene as the sole product, when treated with isopropylmagnesium bromide, nickel dichloride and triphenylphosphine, and t-butylbenzene as the major product, when treated with isopropylmagnesium bromide and (1,3-diphenylphosphinopropane)nickel dichloride.
Ketenethioacetal C(,6)H(,5)CH(,2)CH=C(SEt)(,2) underwent reaction with Grignard reagents in the presence of phosphine-nickel complexes to produce vinyl sulfides in which the alkyl group is oriented trans to the initial benzyl group. When exposed to an excess of methylmagnesium bromide and (1,3-diphenylphosphinopropane)nickel dichloride, the thioacetal produced 1-phenyl-3-methyl-2-butene.
Reaction of enol sulfides of ketones with Grignard reagents in the presence of the aforementioned nickel catalyst produced di- and tri-substituted olefins with retention of configuration at the sulfur-bearing olefinic carbon site.
The reaction between 1,1-diethylthioethylene and phenylmagnesium bromide in the presence of nickel dichloride and triphenylphosphine led to (alpha)-ethylthio styrene, 1,1-diphenylethene and unreacted ketenethioacetal. |
