Solvent‐Mediated C3/C7 Regioselective Switch in Chiral Phosphoric Acid‐Catalyzed Enantioselective Friedel‐Crafts Alkylation of Indoles with α‐Ketiminoesters
作者:Yunlong Zhao、Lu Cai、Tongkun Huang、Shanshui Meng、Albert S. C. Chan、Junling Zhao
DOI:10.1002/adsc.201901380
日期:2020.3.17
The first solvent‐mediated tunable C3/C7 regio‐ and enantioselective Friedel‐Crafts alkylation of 4‐aminoindoles with α‐ketimino esters has been developed. This catalysis allows the highly regioselective formation of indole C3 and C7 alkylation products, both in high yields (up to 96%) and excellent enantioselectivities (up to 99% ee). Mechanism study revealed that the hydrogen‐bonding interactions
Despite the remarkable advances in catalytic asymmetricaziridinations over the past decades, establishing a general procedure for the stereoselective synthesis of trisubstituted aziridines has remained an elusive goal. Chiral N-triflyl phosphoramide-catalyzed reactions of N-α-diazoacyl oxazolidinones and N-Boc imines were developed as a solution to this unmet challenge.
We report the enantiodivergent reaction of ketimines derived from α-ketoesters with malononitriles using a singlechiral source. The reactions using an 8-quinolinesulfonyl cinchona alkaloid catalyst in the presence and absence of Et2Zn gave bothenantiomers in high yields with high enantioselectivities (53∼99% yield, 99:1∼3:97 er). The obtained malononitrile-derived α-amino acids were converted into
我们报告了使用单一手性源的 α-酮酯衍生的酮亚胺与丙二腈的对映发散反应。在存在和不存在 Et 2 Zn的情况下,使用 8-喹啉磺酰基金鸡纳生物碱催化剂的反应以高产率和高对映选择性(产率 53~99%,99:1~3:97 er)得到两种对映异构体。将所得丙二腈衍生的α-氨基酸转化为各种光学活性化合物。提出了一种反应机制来解释观察到的对映异构性。