Pd-catalyzed Heck reactions of aryl bromides with 1,2-diarylethenes

Journal of the Brazilian Chemical Society

Jones Limberger¹  Silvia Poersch¹  Adriano L Monteiro¹ 

[1] ,Universidade Federal do Rio Grande do Sul Instituto de Química Laboratory of Molecular CatalysisPorto Alegre RS ,Brazil

关键词: Heck reaction;    palladium;    trisubstituted olefins;    double arylation;   

DOI  :  10.1590/S0103-50532011000700026

来源: SciELO

【 摘 要 】

A catalytic system composed of Pd(OAc)2 and P(o-tol)3 was found to be effective for the Heck reaction of aryl bromides with diarylethylenes. Using K2CO3 as a base and DMF as a solvent, trisubstituted olefins were obtained in good to excellent yields. Aryl bromides containing an electron-withdrawing group in para position were less reactive for the Heck coupling reaction and gave substantial amount of homocoupling by-product suggesting that oxidative addition is not the rate-determining step. Electron withdrawing group substituent in the para position of stilbene affects the regioselectivity of the reaction. In this case, the phenyl group from the Ph-Pd complex migrates preferentially to the same carbon of the double bond to which the phenyl is bonded. Finally, a one pot sequential double Heck arylation of styrene was performed, giving trisubstituted olefin with an overall yield of 73%.

【 授权许可】

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