High-Throughput Screening of the Asymmetric Decarboxylative Alkylation Reaction of Enolate-Stabilized Enol Carbonates
作者:Brian Stoltz、Nolan McDougal、Scott Virgil
DOI:10.1055/s-0030-1258094
日期:2010.7
The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing to a nonpolar reaction solvent and to an electron-deficient PHOX derivative as ligand from our standard reaction conditions improved the enantioselectivity for the alkylation of a ketal-protected,1,3-diketone-derived enol carbonate from 28% ee to 84% ee. Similar improvements in enantioselectivity were seen for a β-keto ester derived and an α-phenyl cyclohexanone-derived enol carbonate.
利用高通量筛选技术优化了钯催化烯醇稳定烯醇碳酸盐不对称脱羧烷基化反应的反应条件。将标准反应条件改为非极性反应溶剂和缺电子的 PHOX 衍生物作为配体后,酮保护的 1,3-二酮衍生烯醇碳酸酯烷基化反应的对映体选择性从 28% ee 提高到 84%ee。δ-酮酯衍生的烯醇碳酸酯和δ-苯基环己酮衍生的烯醇碳酸酯的对映体选择性也有类似的改善。