Regio- and Enantioselective Pd-Catalyzed Allylic Alkylation of Ketones through Allyl Enol Carbonates
作者:Barry M. Trost、Jiayi Xu
DOI:10.1021/ja043472c
日期:2005.3.9
ketones occurs asymmetrically in the presence of chiral ligands previously developed in this group. With 2-methylcyclohexanone, asymmetric regioselective alkylation occurs at the more substituted carbon without complications of polyalkylation. Alkylation to create quaternary centers in indanones and benzonabenone occurs in much higher ee than using tin or lithiumenolates. The sense of enantioinduction in
在该组先前开发的手性配体存在下,Pd 催化的烯醇烯丙基碳酸酯重组为烯丙基化酮是不对称的。使用 2-甲基环己酮,不对称区域选择性烷基化发生在更多取代的碳上,而没有多烷基化的并发症。在茚满酮和苯并苯酮中产生四元中心的烷基化发生的 ee 比使用锡或烯醇锂高得多。四氢萘酮中的对映诱导意义与烯醇化锡和锂的例子相反。第一次,在高 ee (78-99%) 的情况下,第三中心的不对称创建发生了。该反应与使用锂或烯醇锡之间的不同结果表明可能涉及不同的机制。
Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation of Enol Carbonates
作者:Barry M. Trost、Jiayi Xu、Thomas Schmidt
DOI:10.1021/ja9053948
日期:2009.12.30
extended to a variety of cyclic or acyclic disubstituted allyl groups. Our mechanistic studies reveal that, similar to the direct allylation of lithium enolates, the DAAA reaction proceeds through an "outer sphere" S(N)2type of attack on the pi-allylpalladium complex by the enolate. An important difference between the DAAA reaction and the direct allylation of lithium enolates is that in the DAAA reaction