这项工作首次展示了在具有高耐湿性和抗堵塞性的环境条件下,有机金属反应在流动中的连续、稳定和安全运行。添加低共熔溶剂 (DES),例如甘油(氯化胆碱/甘油)和重新碱(氯化胆碱/尿素),克服了之前与低温条件(长停留时间和高能量需求)和堵塞相关的限制. 不同溶剂的不混溶性导致分段流动,其中反应性有机底物分散在连续的含 DES 载体相中。该系统提供溶剂之间的紧密接触,有利于锂物质(副产品)溶解到 DES 相中,避免在各种条件下发生堵塞。此外,微流体秤提供出色的热管理(再循环流动模式)和高表面积/体积比,从而实现安全操作。通过选择两种有机锂和两种有机镁试剂以及不同的亚胺/酮底物,研究了 DES 的优势。
Introducing Deep Eutectic Solvents to Polar Organometallic Chemistry: Chemoselective Addition of Organolithium and Grignard Reagents to Ketones in Air
作者:Cristian Vidal、Joaquín García-Álvarez、Alberto Hernán-Gómez、Alan R. Kennedy、Eva Hevia
DOI:10.1002/anie.201400889
日期:2014.6.2
Despite their enormous synthetic relevance, the use of polar organolithium and Grignardreagents is greatly limited by their requirements of low temperatures in order to control their reactivity as well as the need of dry organic solvents and inert atmosphere protocols to avoid their fast decomposition. Breaking new ground on the applications of these commodity organometallics in synthesis under more
An efficient oxytrifluoromethylation of 1-aryl-substituted allylalcohols has been developed using Togni’s reagent II as a trifluoromethylation reagent and copper(I) chloride as a catalyst. This reaction proceeded through a one-pot process of trifluoromethylation followed by nucleophilic attack of the vicinal hydroxyl group. This strategy features good diastereoselectivity and broad substrate scope
已使用 Togni 试剂 II 作为三氟甲基化试剂和氯化铜 (I) 作为催化剂开发了 1-芳基取代的烯丙醇的有效氧三氟甲基化。该反应通过三氟甲基化的一锅法进行,然后是邻羟基的亲核攻击。该策略具有良好的非对映选择性和广泛的底物范围,可以轻松获得各种 2-芳基-3-(2,2,2-三氟乙基)环氧乙烷。
Asymmetric Synthesis of α,α-Disubstituted Allylic Amines through Palladium-Catalyzed Allylic Substitution
作者:Wusheng Guo、Aijie Cai、Jianing Xie、Arjan W. Kleij
DOI:10.1002/anie.201705825
日期:2017.9.18
N‐alkyl allyl amine scaffolds through allylic substitution is reported. This approach is based on palladium catalysis and features ample scope with respect to both the allylic precursor and amine reagent, and high asymmetric induction with enantiomeric ratios (e.r.) up to 98.5:1.5. The use of less‐reactive anilines is also feasible, providing enantioenriched α,α‐disubstituted N‐aryl allylicamines.