Enantioselective Reduction of meso-Cyclic-1,2-dicarboxylic Anhydrides and 1,2-Dicarboximides: Asymmetric Synthesis of Bicyclic Lactones and Hydroxylactams.
贵金属技术的替代以及利用地球上丰富的金属实现新的反应性是可持续合成的核心。迄今为止,烯烃加氢最有效地是通过贵金属催化剂进行的。本研究报道了一种铁催化的三取代和四取代烯烃氢化方案,该方案在温和条件(1-4 bar H 2,20 °C)下具有前所未有的活性和范围。通过分离充当催化剂库和颗粒生长的可溶种子的新型铁纳米簇结构,记录了均相和非均相铁催化界面的指导性快照。
Synthesis of Lactams by Regioselective Reduction of Cyclic Dicarboximides
作者:Maria J. Milewska、Tomasz Bytner、Tadeusz Połoński
DOI:10.1055/s-1996-4405
日期:1996.12
Lactams can be obtained by the monothionation of imides with Lawesson’s reagent followed by the desulfurization of resulted monothioimides with Raney nickel.
作者:Isuru Dissanayake、Jacob D. Hart、Emma C. Becroft、Christopher J. Sumby、Christopher G. Newton
DOI:10.1021/jacs.0c06306
日期:2020.8.5
5-Bis(tert-butyldimethylsilyloxy)furans are established as vicinal bisketene equivalents for application as dienes in the Diels-Alderreaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted para-hydroquinones in unprotected form via a one-pot Diels-Alder/ring-opening/tautomerization sequence. The synthesis of para-benzoquinones from
Olefin-Stabilized Cobalt Nanoparticles for C=C, C=O, and C=N Hydrogenations
作者:Sebastian Sandl、Felix Schwarzhuber、Simon Pöllath、Josef Zweck、Axel Jacobi von Wangelin
DOI:10.1002/chem.201705366
日期:2018.3.7
hazardous reductants, special reaction conditions, and the formation of highly unstable pre‐catalysts. Reduction of CoBr2 with LiEt3BH in the presence of alkenes led to the formation of hydrogenation catalysts that effected clean conversions of alkenes, carbonyls, imines, and heteroarenes at mild conditions (3 mol % cat., 2–10 bar H2, 20–80 °C). Poisoning studies and nanoparticle characterization by
结合了易接近性和高选择性的钴催化剂的开发构成了在氢化反应中替代贵金属催化剂的有前途的方法。本报告介绍了一种用户友好的规程,避免了复杂的配体,危险的还原剂,特殊的反应条件以及高度不稳定的预催化剂的形成。在烯烃存在下用LiEt 3 BH还原CoBr 2导致形成加氢催化剂,该催化剂在温和条件下(3 mol%的催化剂,2-10 bar H 2,可实现烯烃,羰基,亚胺和杂芳烃的干净转化)20–80°C)。通过TEM,EDX和DLS进行的中毒研究和纳米颗粒表征支持了异位催化机制的概念。
Photo-Fries-type rearrangement of cyclic enamides. An efficient route to structurally diverse five-membered enaminones
作者:Piotr Szcześniak、Bartłomiej Furman
DOI:10.1039/d1cc06297b
日期:——
A simple, efficient and user-friendly protocol for the preparation of structurally diverse enaminones from enamides has been developed. The strategy is based on a photo-induced intramolecular Fries-type rearrangement. The photochemicaltransformation proceeds under mild reaction conditions, applies to a broad substrate range, is highly economic, and limits the amount of waste produced. The proposed
Specific phenylalanine derivatives or pharmaceutically acceptable salts thereof have an antagonistic effect on the α4 integrins and, therefore, are usable as therapeutic agents or preventive agents for diseases in which α4 integrin-depending adhesion process participates in the pathology, such as inflammatory diseases, rheumatoid arthritis, inflammatory bowel diseases, systemic lupus erythematosus, multiple sclerosis, Sjögren's syndrome, asthma, psoriasis, allergy, diabetes, cardiovascular diseases, arterial sclerosis, restenosis, tumor proliferation, tumor metastasis and transplantation rejection.