Molecular and Merrifield supported chiral diamines for enantioselective addition of ZnR2 (R = Me, Et) to ketones
作者:Mercedes Calvillo-Barahona、Carlos Cordovilla、Miroslav N. Genov、Jesús M. Martínez-Ilarduya、Pablo Espinet
DOI:10.1039/c3dt51097b
日期:——
reported as active catalysts in the enantioselective addition reactions of ZnR2 to either methyl- or trifluoromethyl-ketones. Subtle changes in the molecular structure of different catalysts are described herein and lead to a dramatic effect in their catalyticactivity. From these findings, we demonstrate the selective reactivity of the ligands used in the addition of ZnR2 (R = Me, Et) to methyl- and tri
The catalytic, nucleophilic enantioselective trifluoromethylation reaction of both acyclic and cyclic aryl ketones using the Ruppert-Prakash reagent is now at hand, with an operationally simple procedure, based on the combination of ammonium bromide of cinchonaalkaloids with TMAF. The procedure is reliable and general. Trifluoromethyl-substituted tetrasubstituted aryl alcohols have been synthesized
Highly enantioselective addition of dimethylzinc to fluorinated alkyl ketones, and the mechanism behind it
作者:Tomaz Neves-Garcia、Andrea Vélez、Jesús M. Martínez-Ilarduya、Pablo Espinet
DOI:10.1039/c8cc06358c
日期:——
Chiral-diamine catalyzed addition of ZnMe2 to PhC(O)CF2X (in dichloromethane at −30 °C) affords fluorinated alkyl tertiary alcohols in high yield (quantitative for X = H, F, Cl; 84% for X = CF3) and up to 99% ee. These conditions are similarly very efficient for other various ArC(O)CF3 molecules. A fine analysis of the results can be performed based on a double-cycle mechanism.
将手性二胺催化的ZnMe 2加到PhC(O)CF 2 X中(在-30°C的二氯甲烷中),可以得到高产率的氟化烷基叔醇(X = H,F,Cl定量; X = CF的定量为84%)3)和高达99%的ee。这些条件对于其他各种ArC(O)CF 3分子同样非常有效。可以基于双循环机制对结果进行精细分析。