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首页> 外文期刊>Chemistry: A European journal >Palladium-Catalyzed Cascade Reaction of alpha,beta-Unsaturated Sulfoes with Aryl Iodides
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Palladium-Catalyzed Cascade Reaction of alpha,beta-Unsaturated Sulfoes with Aryl Iodides

机译：钯催化的α，β-不饱和磺基与芳基碘化物的级联反应

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摘要

Unlike traditionally used acyclic 1,2-disubstituted alkenes, the reaction of alpha,beta-unsaturated phenyl sulones with aryl iodides under heck reaction conditions (Pd(OAc)_2 as catalyst, Ag_(2-) CO_3 as base in DMF at 120 deg C) takes place mainly by a cascade process, involving one unit of the alkene and three units of the aryl iodide, to afford a substituted 9-phenylsulfonyl-9,10-dihydrophenanthrene. The dominant formation of this 3:1 coupling product, instead of the Heck trisubstituted olefin, shows that aromatic C-H activation processes can compete with the usually fast syn beta-hydrogen elimination step in the Heck arylation of an acyclic olefin. The structural scope of this palladium-catalyzed cascade arylation of alpha,beta-unsaturated sulfones has proved to be wide with regard to substitution at the beta-position (alkyl, aryl, or alkenyl substitution), substitution at the sulfone unit (alkyl or phenyl sulfones),and configuration at the C=C bond (trans or cis). Moreover, although less favored than in the case of the arylation of alpha,beta-unsaturated sulfones, similarly substituted 9,10-dihydrophenanthrenes have also been obtained in the case of alpha,beta-unsaturated phosphine oxides and alpha,beta-unsaturated phosphonate esters. A Pd~0-Pd~(II)-Pd~(IV) mechanistic pathway involving the successive formation of highly electrophilic sigma-alkylpalladium intermediates and palladacycles is proposed for this multi-component arylation.
机译：与传统上使用的无环1,2-二取代烯烃不同，α，β-不饱和苯基与癸基碘在严格的反应条件下反应（以Pd（OAc）_2为催化剂，Ag_（2-）CO_3为DMF在120°C下的碱） C）主要通过级联方法进行，包括一个单元的烯烃和三个单元的芳基碘，以提供取代的9-苯基磺酰基-9，10-二氢菲。该3：1偶联产物而不是Heck三取代烯烃的主要结构表明，芳族C-H活化过程可以与无环烯烃Heck芳基化反应中通常快速的合成β-氢消除步骤竞争。事实证明，钯催化的α，β-不饱和砜的级联芳基化的结构范围很广，包括在β位的取代（烷基，芳基或烯基取代），在砜单元的取代（烷基或苯基）。砜）和C = C键的结构（反式或顺式）。此外，尽管不如在α，β-不饱和砜芳基化的情况下受到青睐，但在α，β-不饱和氧化膦和α，β-不饱和膦酸酯的情况下，也获得了类似取代的9，10-二氢菲。 。提出了一种Pd〜0-Pd〜（II）-Pd〜（IV）机理途径，涉及到高亲和力的sigma-烷基钯中间体和palladacycles的连续形成。

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