One-pot dialkylation of allylphenylsulfide induced by aminoalkoxides-activated NaNH2. Application to the synthesis of unsymmetrical ketones
作者:Sabine Choppin、Philippe Gros、Yves Fort
DOI:10.1016/s0040-4020(99)00481-0
日期:1999.7
aminoalkoxides, leading to new superbases, induced an efficient one-pot dialkylation of allylphenylsulfide. The regioselectivity of the reaction (α,α′ vs α,γ) was found as strongly dependent on the nature of the alkyl halide. As an application, α,γ dialkylated products were efficiently converted into the corresponding unsymmetrical ketones.
elimination of arene- and alkanethiol from diaryl and dialkyl dithioacetals, in the presence of copper(I) or copper(II) salt plus tertiary amine, to produce the corresponding aryl and alkyl vinyl sulfides, respectively, has been studied. The employment of a combination of 2 mol equiv. of CuCl2 and 2 mol equiv. of N,N-diisopropylethylamine is most favorable.
The title reaction in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) affords alkylative coupling products in good to excellent yields in 1,2-dichloroethane at room temperature. This coupling reaction under C(sp2)–O cleavage proceeds stereospecifically. The reaction does not affect a coexisting vinyl sulfide group. This feature enables 1,2- and 1,3-carbonyl transposition
Abstract The radical reaction of benzenethiol with alkynes 1a-o carried out at 154 °C affords a mixture of thiol/alkyne adduct 3 and benzothiophene 5, deriving from vinyl radical intermediates 2 through hydrogen abstraction and 5-(π-endo)orthocyclization onto the adjacent thiophenyl ring, respectively. This latter reaction occurs through the reversible formation of cyclohexadienyl radical intermediates
Keto carbonyl 1,2- and 1,3-transpositions with and without alkylation of the substrate are described together with ketone synthesis from thiocarboxylic S-ester.