Novel Ruthenium-Catalyzed Synthesis of Polycarboxylic Acid Derivatives

脂肪族多羧酸衍生物和芳香族多羧酸衍生物都是化学工业中非常重要的中间体。在这项研究中，我们开发了以下新的钌催化合成多羧酸衍生物，涉及交叉偶联和环加成反应。首先，通过C-C键裂解，钌催化环丙烯羰基二聚化反应制备了吡喃吡啶酮。例如，以Ru_3(CO) <12>和NEt_3为催化剂，在15 atm的一氧化碳和140℃的THF中处理二丙基环丙烯20 h，得到新的功能单体3,4,7,8-四丙基吡喃[6,5-e]吡喃-2,6-二酮，分离收率为81%。在类似的反应条件下，钌催化环丙烯与炔的羰基偶联也得到了不对称取代的吡喃吡啶酮。本研究制备的吡喃吡喃二酮类化合物均为新化合物，由于其具有更独特的物理和化学性质，作为新型功能单体具有很大的吸引力。然后，建立了由Cp*RuCl(cod)/PPh_3 [Cp* =五甲基环戊二烯，cod 1,5-环戊二烯]组成的催化剂体系，用于二烷基乙基二羧酸酯与烯丙基化合物的新型交叉苯并反应。举例来说，在4 mol % Cp*RuCl（cod）和PPh_3存在下，乙酰二甲酸二甲酯与烯丙醇在甲苯回流条件下反应5 h，得到5-甲基-1,2,3,4-苯四甲酸四甲酯，分离收率为84%。此外，利用钌催化剂Cp*RuCl(cod)，成功地完成了2 eqiv末端炔与二甲基乙炔二羧酸酯的高化学选择性分子间[2 + 2 + 2]环加成，使二烷基化邻苯二甲酸酯的直接合成成为可能。炔和乙炔二羧酸共环三聚化反应通常产生1:2的加合物（1,2,3,4-苯四羧酸酯），但在本反应中，2:1的加合物（邻苯二甲酸酯）是前所未有的主要产物。最近，我们还报道了新的零价钌配合物Ru(η^6-cot)(dmfm)_2，它在2,5-降冰片二烯的独特二聚化反应中表现出很高的催化活性，新的半笼型化合物PCTD [pentacyclo[6.6.0.0^<2,6>.0^<3,13>.0^<10,14>]四溴-4,11-二烯]。进一步研究了该配合物的反应活性，发现与对醌反应生成Ru(η^6-cot)（对醌）配合物，与芳烃反应生成新型（η^6-芳烃）Ru(dmfm)_2配合物。所有的反应都是在Ru(η^6-cot)(dmfm)_2中通过cot和/或dmfm的直接配体交换反应进行的，所制备的新配合物有望作为合成脂肪族和芳香族多羧酸衍生物的有效催化剂。少

Both aliphatic and aromatic polycarboxylic acid derivatives are highly important intermediates in chemical industry. In this study, we developed the following novel ruthenium-catalyzed syntheses of polycarboxilic acid derivatives involving cross-coupling and cycloaddition reactions. First, pyranopyrandiones were prepared by a novel ruthenium-catalyzed carbonylative dimerization of cyclopropenones via C-C bond cleavage. For example, treatment of dipropylcyclopropenone with a catalytic amount of Ru_3(CO)_<12> and NEt_3 in THF under 15 atm of carbon monoxide at 140℃ for 20 h gave a novel functional monomer, 3,4,7,8-tetrapropylpyrano[6,5-e]pyran-2,6-dione, in an isolated yield of 81%. Unsymmetrically substituted pyranopyrandiones were also obtained by ruthenium-catalyzed carbonylative coupling of cyclopropenones with alkynes under similar reaction conditions. All pyranopyrandiones prepared in this study are new compounds, which are quite attractive as novel functional monomers due to their … More characteristic physical and chemical properties. Then, a catalyst system consisting, of Cp*RuCl(cod)/PPh_3 [Cp* = pentamethylcyclopentadienyl, cod 1,5-cyclooctadiene] for the novel cross-benzannulation of 2 equip of dialkyl acetylenedicarboxylate with an allylic compound has been developed. As an example, the reaction of dimethyl acetylenedicarboxylate with allyl alcohol in the presence of 4 mol % Cp*RuCl(cod) and PPh_3 under reflux in toluene for 5 h gave tetramethyl 5-methyl-1,2,3,4-benzenetetracarboxylate in an isolated yield of 84%. Furthermore, a highly chemoselective intermolecular [2 + 2 + 2] cycloaddition of 2 eqiv of terminal alkynes with dimethyl acetylenedicarboxylate, which enables the straightforward synthesis of dialkylated o-phthalates, was successfully accomplished using a ruthenium catalyst, Cp*RuCl(cod). The co-cyclotrimerization of alkynes and acetylenedicarboxylates usually affords 1:2 adducts (1,2,3,4-benzenetetracarboxylates), however, in the present reaction 2:1 adducts (o-phthalates) are the major products unprecedentedly. Recently, we have also reported the novel zerovalent ruthenium complex Ru(η^6-cot)(dmfm)_2, which showed high catalytic activity in a unique dimerization of 2,5-norbornadiene to novel half-cage compounds, PCTD [pentacyclo[6.6.0.0^<2,6>.0^<3,13>.0^<10,14>]tetradeca-4,11-diene]. During our further investigation of the reactivity of this complex, we found that the reaction with p-quinones gave Ru(η^6-cot)(p-quinone) complexes, while the reaction with arenes gave novel (η^6-arene)Ru(dmfm)_2 complex. All reactionsproceeded via the direct ligand exchange reactions of cot and/or dmfm in Ru(η^6-cot)(dmfm)_2, and the new complexes prepa-red here can be expected as efficient catalysts for the synthesis of aliphatic and aromatic polycarboxylic acid derivatives. Less