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Diastereospecific Bis‐alkoxycarbonylation of 1,2‐Disubstituted Olefins Catalyzed by Aryl α‐Diimine Palladium(II) Catalysts
Advanced Synthesis & Catalysis ( IF 5.4 ) Pub Date : 2018-04-20 , DOI: 10.1002/adsc.201701597
Diego Olivieri 1 , Francesco Fini 2 , Rita Mazzoni 1 , Stefano Zacchini 1 , Nicola Della Ca' 3 , Gilberto Spadoni 4 , Bartolo Gabriele 5 , Raffaella Mancuso 5 , Valerio Zanotti 1 , Carla Carfagna 1
Affiliation  

Readily synthesized aryl α‐diimine derivatives have been used as efficient ligands for the palladium‐catalyzed oxidative bis‐alkoxycarbonylation reaction of 1,2‐disubstituted olefins. The most active catalyst A was formed in situ from bis‐(2,6‐dimethylphenyl)‐2,3‐dimethyl‐1,4‐diazabutadiene and Pd(TFA)2 (TFA=trifluoroacetate). This catalytic system was able to selectively convert 1,2‐disubstituted olefins into 2,3‐disubstituted‐succinic diesters with total diastereospecificity, in good yields (up to 97%) with 2 mol% of catalyst loading, under mild reaction conditions (4 bar of CO at 20 °C in presence of p‐ toluenesulfonic acid as additive and p‐benzoquinone as oxidant). The optimized reaction conditions could be successfully applied to 1,2‐disubstituted aromatic, aliphatic, cyclic olefins and to unsaturated fatty acid methyl esters, employing methanol or benzyl alcohol as nucleophiles. The use of the bulky, less reactive isopropyl alcohol has allowed to better understand the mechanisms involved in the catalytic process. The geometry of the carbonylated products can be explained as a consequence of a concerted syn addition of the Pd‐alkoxycarbonyl moiety to the olefin C=C bond. Catalyst A was isolated, characterized and analyzed by single crystal X‐ray diffraction analysis.

中文翻译:

芳基α-二胺钯(II)催化剂催化1,2-双取代烯烃的非对映体双烷氧基羰基化

易于合成的芳基α-二亚胺衍生物已用作钯催化的1,2-二取代烯烃的氧化双烷氧基羰基化反应的有效配体。活性最高的催化剂A是由双(2,6-二甲基苯基)-2,3-二甲基-1,4-重氮杂丁二烯和Pd(TFA)2(TFA =三氟乙酸盐)原位形成的。该催化体系能够在温和的反应条件下,以2摩尔%的催化剂负载量,将具有总非对映特异性的1,2-二取代的烯烃选择性转化为2,3-二取代的琥珀酸二酯,收率高(高达97%)(4在有甲苯磺酸作为添加剂和p的存在下于20°C的CO的bar-苯醌作为氧化剂)。使用甲醇或苯甲醇作为亲核试剂,优化的反应条件可以成功地应用于1,2-二取代的芳族,脂肪族,环状烯烃和不饱和脂肪酸甲酯。使用体积大,反应性较小的异丙醇可以更好地了解催化过程中涉及的机理。所述羰基化产物的几何形状可以为一致的结果进行说明顺式加入钯-烷氧羰基部分的所述烯烃的C = C键。通过单晶X射线衍射分析分离,表征和分析催化剂A。
更新日期:2018-04-20
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