6- and 14-Fluoro farnesyl diphosphate: mechanistic probes for the reaction catalysed by aristolochene synthase
作者:David J. Miller、Fanglei Yu、David W. Knight、Rudolf K. Allemann
DOI:10.1039/b817194g
日期:——
enzyme aristolochene synthase from Penicillium roqueforti (PR-AS) has been probed with the farnesyldiphosphateanalogues 6- and 14-fluoro farnesyldiphosphate (1b and 1c). Incubation of these analogues with PR-AS followed by analysis of the reaction products by GC-MS and NMR spectroscopy indicated that these synthetic FPP analogues were converted to the fluorinated germacrene A analogues 3b and 3c, respectively
palladium/XPhos complex and 5-norbornene-2-carboxylic acid was developed. This system promotes a two-component annulation reaction, allowing the construction of tetrahydronaphthalenes and indanes that contain quaternary centers through consecutive Catellani-type C–H activation and redox-relay Heck reaction. Inexpensive 5-norbornene-2-carboxylic acid acts as a catalytic mediator (20 mol %) in this process. This mild
[EN] DEUTERATED PHENOL DERIVATIVES, PREPARATION METHOD THEREFOR, AND USE THEREOF<br/>[FR] DÉRIVÉS DE PHÉNOL DEUTÉRÉS, LEUR PROCÉDÉ DE PRÉPARATION ET LEUR UTILISATION<br/>[ZH] 氘代苯酚衍生物及其制备方法和用途
Mediators play a central role in Catellani-type reactions. Herein we reported the discovery of inexpensive 5-norbornene-2-carboxylic acid (N-4) as a general catalytic mediator (20 mol%) to facilitate ortho C-H activation and the following C-C bond formation of aryl iodides. Firstly, a cooperative catalytic system comprising N-4 and a palladium/XPhos complex was developed for the novel Catellani/redox-relay Heck cascade to construct tetrahydronaphthalenes and indanes that contain a quaternary carbon stereogenic center. The striking feature of this work was the avoidance of stoichiometric NBE mediator that are usually required for Catellani-type reactions. Then, preliminary results demonstrated that N-4 could act as a general catalytic mediator to replace NBE for other Catellani-type reactions, which will undoubtedly inspire future developments in the field of cooperative catalysis. Finally, control experiments indicated that the carboxylic acid moiety of N-4 plays an essential role in its ability to serve as a superior mediator. (C) 2019 Elsevier Ltd. All rights reserved.
Leukotriene antagonists
申请人:BAYER AG
公开号:EP0410244A1
公开(公告)日:1991-01-30
Leukotriene antagonists are disclosed comprising compounds having the general formula represented by the formula shown below, esters, amides and physiologically acceptable salts thereof. These compounds retain the natural 5(S) 6(R) configuration, the 5-hydroxyl group and the natural unsaturated tail with the peptide replaced by a substituted aromatic nucleus linked via a sulfur or oxygen substituent linking a substituent to the 6 position.