Acid—Base Catalysis of Chiral Pd Complexes: Development of Novel Asymmetric Reactions
Acid—Base Catalysis of Chiral Pd Complexes: Development of Novel Asymmetric Reactions
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手性钯配合物的酸碱催化：新型不对称反应的发展
DOI：
10.1002/chin.200609253
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Y. Hamashima
中科院分区：
文献类型：
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作者：
Y. Hamashima
利用手性钯配合物1和2的独特性质，已经开发了几种新型的催化不对称反应。与常规Pd（0）催化的反应相反，这些络合物充当酸碱催化剂。因此，活性次甲基化合物被激活，形成手性钯烯醇化物，其中经历了对映选择性迈克尔反应和曼尼希型反应高达99%ee。有趣的是，这些钯烯醇化物与强质子酸协同作用，激活亲电体，伴随形成的烯醇化物的形成过程中，从而促进CC键形成反应。此外，这种钯烯醇化物化学也适用于亲电不对称氟化反应，因此各种羰基化合物包括β-酮酯、β-酮膦酸酯和羟吲哚以高度对映选择性的方式氟化（高达98%ee）。有利的是，这些反应在环境友好的醇溶剂如乙醇中进行，并且不需要排除空气和水分。
Using a unique character of the chiral palladium complexes 1 and 2, several types of novel catalytic asymmetric reactions have been developed. In contrast to the conventional Pd (0)-catalyzed reactions, these complexes function as an acid-base catalyst. Thus active methine compounds were activated to form chiral palladium enolates, which underwent the enantioselective Michael reaction and Mannich-type reaction with up to 99% ee. Interestingly, these palladium enolates acted cooperatively with a strong protic acid activating the electrophiles, formed concomitantly during the formation of the enolates, whereby the CC bond-forming reaction was promoted. In addition, this palladium enolate chemistry was also applicable to the electrophilic asymmetric fluorination reactions, and thus various carbonyl compounds including β-ketoesters, β-ketophosphonates, and oxindoles were fluorinated in a highly enantioselective manner (up to 98% ee). It is advantageous that these reactions were carried out in environmentally friendly alcoholic solvents such as ethanol, and exclusion of air and moisture is not necessary.