立体选择性炔烃半氢化是制备烯烃的有吸引力的方法,烯烃是合成的关键组成部分。对于最具原子经济性的还原剂二氢(H 2 ),仅公开了少数用于具有挑战性的E-选择性炔烃半氢化的催化剂,每种催化剂都具有独特的底物范围特征。在这里,我们表明,市售的镍催化剂促进了多种取代内炔的E-选择性炔烃半氢化。这产生了一个简单且广泛适用的整体方案,用于使用 H 2立体选择性地访问E-烯烃,这可以作为通用的合成方法。
Iron-Catalyzed Tunable and Site-Selective Olefin Transposition
作者:Xiaolong Yu、Haonan Zhao、Ping Li、Ming Joo Koh
DOI:10.1021/jacs.0c08631
日期:2020.10.21
earth-abundant iron-based complex, a base and a boryl compound promote efficient and controllable alkene transposition. Mechanistic investigations reveal that these processes likely involve in situ formation of an iron-hydride species which promotes olefin isomerization through sequential olefin insertion/β-hydride elimination. Through this strategy, regiodivergent access to different products from
CC 双键的催化异构化是必不可少的化学转化,用于提供更高价值的类似物,在化学工业中具有重要用途。尽管在该领域取得了进展,但仍然迫切需要一种通用催化解决方案,能够精确控制环状和非环状体系中的 C=C 键迁移位置,以提供二取代和三取代烯烃。在这里,我们展示了催化量的合适的地球丰富的铁基络合物、碱和硼基化合物促进有效和可控的烯烃转位。机理研究表明,这些过程可能涉及原位形成铁氢化物物种,该物种通过顺序烯烃插入/β-氢化物消除促进烯烃异构化。通过这个策略,
ZrCl2(η-C5Me5)2-AlHCl2·(THF)2: efficient hydroalumination of terminal alkynes and cross-coupling of the derived alanes
作者:Philip Andrews、Christopher M. Latham、Marc Magre、Darren Willcox、Simon Woodward
DOI:10.1039/c2cc37537k
日期:——
with exceptional chemo-, regio- and stereoselectivity under efficient ZrCl(2)(eta-C(5)Me(5))(2) catalysis (2-5 mol%). The resulting vinyl alanes undergo palladium cross-coupling with a wide range of sp(2) electrophiles (aryl, heteroaryl and vinylhalides/pseudohalides) in good to excellent yields.
Using alcohols as simple H<sub>2</sub>-equivalents for copper-catalysed transfer semihydrogenations of alkynes
作者:Trinadh Kaicharla、Birte M. Zimmermann、Martin Oestreich、Johannes F. Teichert
DOI:10.1039/c9cc06637c
日期:——
Copper(I)/N-heterocycliccarbenecomplexes enable a transfersemihydrogenation of alkynes employing simple and readily available alcohols such as isopropanol. The practical overall protocol circumvents the use of commonly employed high pressure equipment when using dihydrogen (H2) on the one hand, and avoids the generation of stoichiometric silicon-based waste on the other hand, when hydrosilanes are
New furanone derivatives, process for the preparation thereof and use thereof
申请人:FUJISAWA PHARMACEUTICAL CO., LTD.
公开号:EP0099692A1
公开(公告)日:1984-02-01
The present invention provides compounds of the formula:-
wherein A is a lower alkylene group; R' is a carboxy, hydroxy, protected hydroxy, lower alkoxycarbonyl, lower alkoxycarbonylamino or lower alkanoyloxy group; R2 is a hydrogen or halogen atom or a halo (lower) - alkyl group; R3 is a hydrogen or halogen atom; R4 is a hydrogen atom or a hydroxy, carboxy, lower alkoxy, lower alkanoyloxy or lower alkoxycarbonyloxy group and R5 is a hydrogen or halogen atom or R4 and R5 together represent the group =CH2; F is the number of double bonds which is equal to 0 or 1 and n is an integer of 0 or 1, with the proviso that when F is 0 then n is 1 and when F is 1 then n is 0; and the pharmaceutically- acceptable salts thereof.
The present invention also provides processes for the preparation of these compounds and pharmaceutical compositions containing them. Futhermore, the present invention is concerned with the use of these compounds for the treatment of diabetic cataract and/or neuropathy.
本发明提供式如下的化合物
其中 A 是低级亚烷基;R'是羧基、羟基、保护羟基、低级烷氧基羰基、低级烷氧基羰基氨基或低级烷酰氧基;R2 是氢原子或卤素原子或卤代(低级)-烷基;R3 是氢原子或卤素原子;R4是氢原子或羟基、羧基、低级烷氧基、低级烷酰氧基或低级烷氧基羰基,R5是氢原子或卤素原子或R4和R5共同代表基团=CH2;F是双键的数目,等于0或1,n是0或1的整数,但当F为0时,n为1,当F为1时,n为0;及其药学上可接受的盐。
本发明还提供了制备这些化合物和含有这些化合物的药物组合物的工艺。此外,本发明还涉及使用这些化合物治疗糖尿病性白内障和/或神经病变。
Mechanochemical aerobic oxidative Heck coupling by polymer-assisted grinding: cyclodextrin additive facilitating regioselectivity control
The oxidative Heckreaction is a well-known organic transformation. However, previous reactions have been limited by the need for sophisticated directing or auxiliary groups, reliance on bulk solvents, lack of catalyst recycling, and the formation of a mixture of isomeric products, thereby hindering its broader application. Herein, we present a novel approach utilizing the polymer-assisted grinding