A new family of phosphine free organometallic ruthenium(II) catalysts (Ru1 –Ru4 ) supported by bidentate NN Schiff base ligands (L¹–L⁴ where L¹=N,N‐dimethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐ylmethyl)hydrazineylidene)methyl) aniline, L²=N,N‐diethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐ylmethyl)hydrazineylidene)methyl)aniline, L³=N,N‐dimethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐yl)hydrazineylidene)methyl)‐ aniline and L⁴=N,N‐diethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐yl)hydrazineylidene)methyl) aniline) was prepared and characterized. These half‐sandwich complexes acted as catalysts for C−C bond formation and exhibited excellent performance in the dehydrogenative coupling of ketones and amides. In the synthesis of C–C bonds, alcohols were utilized as the alkylating agent. A broad range of substrates, including sterically hindered ketones and alcohols, were well tolerated under the optimized conditions (TON up to 47000 and TOF up to 11750 h⁻¹). This ruthenium (II) catalysts were also active towards the dehydrogenative cyclization of o ‐amino benzyl alcohol for the formation of quinolines derivatives. Various polysubstituted quinolines were synthesized in moderate to excellent yields (TON up to 71000 and TOF up to 11830 h⁻¹). Control experiments were carried out and the ruthenium hydride intermediate was characterized to support the reaction mechanism and a probable reaction pathway of dehydrogenative coupling for the C−C bond formation has been proposed.

中文翻译：

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用于醇和酮与酰胺的α-烷基化的高效有机钌催化剂：通过氢借用策略合成喹啉及其机理研究

一个新的无膦有机金属钌（II）催化剂家族（Ru1 - Ru4），由二齿NN Schiff碱配体（L ¹ -L ⁴，其中L ¹ = N，N-二甲基-4-（（2-苯基-2- （吡啶-2-基甲基）肼基）甲基）苯胺，L ² = N，N-二乙基-4-（（2-苯基-2-（甲基-2-基甲基）肼基）甲基）苯胺，L ³ = N， N-2-甲基-4-（（2-苯基-2-（吡啶-2-基）肼基亚甲基）甲基）苯胺和L ⁴= N，N-二乙基-4-（（2-苯基-2-（吡啶-2-基）肼基亚甲基）甲基）苯胺被制备并表征。这些半三明治配合物可作为C-C键形成的催化剂，在酮和酰胺的脱氢偶联中表现出出色的性能。在CC键的合成中，醇被用作烷基化剂。在最佳条件下（TON高达47000，TOF高达11750 h ^-1），各种各样的底物，包括位阻酮和醇，都具有良好的耐受性。该钌（II）催化剂对o的脱氢环化也具有活性-氨基苄醇，用于形成喹啉衍生物。合成了多种多取代的喹啉，其产率中等至优异（TON高达71000，TOF高达11830 h ^-1）。进行了控制实验，并表征了氢化钌中间体以支持反应机理，并提出了可能的脱氢偶联反应途径形成CC键。