A Bifunctional Copper Catalyst Enables Ester Reduction with H<sub>2</sub>: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
作者:Birte M. Zimmermann、Trung Tran Ngoc、Dimitrios-Ioannis Tzaras、Trinadh Kaicharla、Johannes F. Teichert
DOI:10.1021/jacs.1c09626
日期:2021.10.13
activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered “soft” copper(I) hydrides to previously
采用基于铜 (I)/NHC 配合物和胍有机催化剂的双功能催化剂,促进了以 H 2作为末端还原剂的催化酯还原成醇。这里采用的方法能够通过氢键同时活化酯,并从 H 2形成亲核的氢化铜 (I) ,从而导致氢化物催化转移到酯。由胍亚基介导的质子穿梭进一步促进了还原步骤。这种酯还原的双功能方法首次将通常认为的“软”氢化铜 (I) 的反应性转变为以前不反应的“硬”酯亲电子试剂,并为用催化剂和 H 2替代化学计量还原剂铺平了道路.
O-Alkyl S-(Pyridin-2-yl)carbonothiolates: Operationally Simple and Highly Nitrogen-Selective Reagents for Alkoxy Carbonylation of Amino Groups
Amino groups are selectively protected in good yields by reaction with O-alkyl S-(pyridin-2-yl)carbonothiolates in an appropriate solvent at room temperature in air. Even glucosamine, which contains multiple hydroxyl groups, is selectively N-protected in methanol.
通过与 O-烷基 S-(吡啶-2-基)碳硫醇盐在适当的溶剂中在室温下在空气中反应,氨基以良好的产率被选择性地保护。甚至含有多个羟基的葡糖胺也在甲醇中被选择性地 N 保护。
SUBSTITUTED SULFONAMIDE COMPOUNDS
申请人:Reich Melanie
公开号:US20090275558A1
公开(公告)日:2009-11-05
Substituted sulfonamide compounds corresponding to formula I
processes for the preparation thereof, pharmaceutical compositions containing such compounds, and the use of such compounds for treating and/or inhibiting pain or other conditions at least partly mediated by the bradykinin 1 receptor.
δ,ϵ-Unsaturated oximes, on heating with O-alkyl S-(pyridin-2-yl)carbonothioates (PySCO2R) in refluxing toluene, undergo intramolecular cycloaddition to give N-alkoxycarbonylated multi-cyclic compounds. Mechanistic studies indicate that the reaction involves direct generation of N-alkoxycarbonyl nitrones followed by cycloaddition, instead of intramolecular oxime-olefin cycloaddition (IOOC) followed