Nitrogen Fixation: Synthesis of Heterocycles Using Molecular Nitrogen as a Nitrogen Source
作者:Miwako Mori、Masaya Akashi、Masanori Hori、Katsutoshi Hori、Mayumi Nishida、Yoshihiro Sato
DOI:10.1246/bcsj.77.1655
日期:2004.9
Nitrogen fixation using transition metals is a fascinating process. We have already reported on the incorporation of molecular nitrogen into organic compounds using a titanium–nitrogen complex reported by Yamamoto. We developed a novel titanium-catalyzed nitrogenation procedure using TiCl4 in the presence of an excess amount of Li and TMSCl. In this reaction, a 1 atm pressure of nitrogen gas can be used and the reaction proceeds at room temperature. The procedure is very simple. A THF solution of TiCl4 or Ti(OiPr)4 (1 equiv.), Li (10 equiv.), and TMSCl (10 equiv.) was stirred under an atmosphere of nitrogen at room temperature overnight to give titanium–nitrogen complexes. Although the structures of the titanium–nitrogen complexes have not yet been determined, they would consist of N(TMS)3, X2TiN(TMS)2, and XTi=NTMS. Using this procedure, various heterocycles, such as indole, quinoline, pyrrole, pyrrolizine, and indolizine derivatives, could be synthesized from molecular nitrogen in good-to-moderate yields as a stoichiometric reaction based on a titanium complex by a one-pot reaction. Furthermore, monomorine I and pumiliotoxin C were synthesized from molecular nitrogen as a nitrogen source. This procedure was further extended for the syntheses of heterocycles using a catalytic amount of titanium complex; also, indole and pyrrole derivatives were obtained in high yields.
Visible-Light Photocatalytic Preparation of 1,4-Ketoaldehydes and 1,4-Diketones from α-Bromoketones and Alkyl Enol Ethers
作者:William H. García-Santos、Jeferson B. Mateus-Ruiz、Alejandro Cordero-Vargas
DOI:10.1021/acs.orglett.9b01275
日期:2019.6.7
A Ru2+-photocatalyzed, visible-light-mediated ATRA reaction for the straightforward preparation of 1,4-ketoaldehydes, 1,4-diketones, and 1,4-ketoesters, which are of difficult access by other means, is reported herein. This method employs readily accessible α-bromoketones and alkyl vinyl ethers as starting materials, allowing the construction of secondary, tertiary, and challenging quaternary centers
[EN] CRTH2 MODULATORS<br/>[FR] MODULATEURS DE CRTH2
申请人:IRONWOOD PHARMACEUTICALS INC
公开号:WO2010039982A1
公开(公告)日:2010-04-08
Modulators of CRTH2, particularly antagonists of CRTH2, that are useful for treating various disorders, including asthma and respiratory disorders are disclosed. The compounds fall within a genus described by formula I.
The decomposition of O,O-tert-butyl and O-isopropenyl peroxycarbonate in cyclanones and oxacylanes leads to acetonylated derivatives of these solvents. Although the reaction mechanism involves in both cases the addition of free radicals derived from solvent to the double bond of the peroxycarbonate, the orientation of the whole process depends on the solvent. In the case of oxacyclanes the relative
Stereocontrolled [m + n] annulation reactions. 3. A convenient approach to seven- and eight-membered carbocycles by a novel annulation process
作者:Gary A. Molander、David C. Shubert
DOI:10.1021/ja00256a066
日期:1987.10
Reactions de composes γ- et δ-dicarbonyles avec SnF 2 et l'iodomethyl-2 allyl trimethyl silane: obtention d'oxa-8bicyclo [3.2.1] octanes et d'oxa-9bicyclo [3.3.1] nonanes