Conversion of Disilanes to Functional Monosilanes. XIII. The Palladium Catalyzed Reductive Coupling of Benzylidene Dichlorides and Benzylidyne Trichlorides Using Disilanes as Reducing Agents
The reaction of benzylidene dichlorides or benzylidyne trichlorides with 1,2-dichloro-1,1,2,2-tetramethyldisilane or hexamethyldisilane proceeded smoothly in the presence of acatalytic amount of Pd(PPh3)4 to give (E)-stilbenes or (E)- and (Z)-α,β-dichlorostilbenes in high yields, respectively. Also, in the presence of the palladium(0) catalyst, α,α-dichlorobenzyltrimethylsilanes reacted with hexamethyldisilane yielding (E)-α,β-bis(trimethylsilyl)stilbenes in quantitative yield.
series of arylmethanesulfonyl chlorides were treated with triethylamine in THF to give stilbenes in excellent yields. Workup of the mixtures below 10 °C permits isolation of stilbene episulfones which on warming decompose to yield the corresponding stilbenes stereospecifically. Application of the reaction to 9-fluorenylsulfonyl chloride affords bifluorenylidene, while trans-styrylmethanesulfonyl chloride
The reaction of benzylidene chlorides as well as 1,2-dihalogeno-1,2-diphenylethanes with sym-dichlorotetramethyldisilane in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) gave aryl-substituted ethenes in good yields.
Stereoselective Synthesis of <i>trans</i>-Stilbenes through Silver-Catalyzed Self-Coupling of <i>N</i>-Triftosylhydrazones: An Experimental and Theoretical Study
作者:Qingmin Song、Yue Zhao、Shaopeng Liu、Yong Wu、Zhaohong Liu
DOI:10.1021/acs.orglett.3c01040
日期:2023.5.19
efficiency with excellent stereoselectivity, broad substrate scope, and good functional group tolerance. A plausible mechanism involving nucleophilic attack of in situ generated sulfonium ylides on silver carbene was proposed on the basis of experimental results and DFT calculations, which further indicates that π–π stacking interactions play a dominant role in stereoselectivity control.