Catalytic Enantioselective Synthesis of Protecting-Group-Free 1,5-Benzothiazepines
作者:Sara Meninno、Chiara Volpe、Alessandra Lattanzi
DOI:10.1002/chem.201700837
日期:2017.4.3
2,3‐dihydro‐1,5‐benzothiazepinones, by an organocatalyzed sulfa‐Michael reaction of readily available α,β‐unsaturated N‐acyl pyrazoles with 2‐aminothiophenols followed by silica‐gel‐catalyzed lactamization, has been developed. The method proceeds under mild conditions at room temperature and it requires only 1 mol % catalyst loading, to give 2‐aryl/alkyl‐substituted 1,5‐benzothiazepines in generally
promising as good dienophiles, which were easily converted into the desired carboxylic derivatives. Bis(pyrazolyl)methanes, which were derived from chiral pyrazoles, showed the activity of chiral catalyst. Particularly 10 mol% of bis(isomenthopyrazol-1,1′-yl)methane (8a) catalyzed enantioselectively the DielsAlder reaction up to 40 % ee by the formation of complex with Mg(ClO4)2.
(<i>R</i>)-DM-SEGPHOS–Ag(I)-Catalyzed Enantioselective Synthesis of Pyrrolidines and Pyrrolizidines via (1,3)- and Double (1,3)-Dipolar Cycloaddition Reactions
作者:Sumit K. Ray、Rayhan G. Biswas、Arun Suneja、Milon M. Sadhu、Vinod K. Singh
DOI:10.1021/acs.joc.7b03185
日期:2018.2.16
diastereo- and enantioselective route to access a wide range of highly substituted pyrrolidine and pyrrolizidine derivatives has been described via (1,3)- and double (1,3)-dipolar cycloaddition reactions catalyzed by the (R)-DM-SEGPHOS–Ag(I) complex. The reactions proceed smoothly at ambient temperature, affording a variety of pyrrolidines and pyrrolizidines in high yields (up to 93%) with up to 99:1 dr and
ASYMMETRICALLY CATALYZED SYNTHESIS METHOD OF NITROPYRAZOLE AMIDE COMPOUND
申请人:Zhejiang Jiuzhou Pharmaceutical Co., Ltd.
公开号:US20170291876A1
公开(公告)日:2017-10-12
A synthesis method of γ-nitropyrazole amide compound through asymmetrical catalyzing technique is provided, a nitroalkane and an α,β-unsaturated pyrazole amide are applied as the raw material, a complex formed by a chiral amine oxide with a rare earth metal compound is served as the catalyst, a 4 Å molecular sieve is served as an additive, the γ-nitropyrazole amide compound can be obtained with a yield more than 99% and enantiomeric excess more than 99% ee. The catalytic system not only has the advantages of simple operation, mild reaction conditions, requiring no acid/base additives, convenient product purification, high yield and enatioselectivity, compliance with green atomic economy, and promising prospects for industrial application, but also allows the obtained γ-nitropyrazole amide compound to undergo some simple chemical conversions to produce some molecules having physiological activities.