Additions of organomanganese reagents to conjugated nitroolefins
摘要:
Additions of organomanganese reagents to aromatic and aliphatic conjugated nitroolefins were examined for the first time. In most cases reaction proceeded rapidly at -30 degrees C. Unlike Mn reagents lacking beta-hydrogens (Me, Ph), which lead to oxidative coupling and reductive dimerisation of nitrostyrenes, benzylmanganese chloride gives 1,4-addition in yields exceeding Grignard or Cu-assisted additions. At 0 degrees C alkyl(Bu, Pr)-manganese reagents undergo an addition-migration-elimination process with nitrostyrenes providing a convenient and stereospecific entry into arylated trans-olefins.
Direct preparation of benzylic manganese reagents from benzyl halides, sulfonates, and phosphates and their reactions: applications in organic synthesis
作者:YoungSung Suh、Jun-sik Lee、Seoung-Hoi Kim、Reuben D Rieke
DOI:10.1016/s0022-328x(03)00500-x
日期:2003.11
The use of highly active manganese (Mn)*, prepared by the Rieke method, was investigated for the direct preparation of benzylic manganese reagents. The oxidative addition of the highly active manganese to benzylic halides was easily completed under mild conditions. Moreover, benzylic manganese sulfonates and phosphates were prepared by direct oxidative addition of Mn* to the carbon–oxygen bonds of
The use of FeCl2 (10 mol%) allows a convenient iron-catalyzed cross-coupling reaction of benzylic manganese(II) chlorides with various aryl and heteroaryl chlorides, bromides and iodides leading to polyfunctionalized diaryl- and arylheteroarylmethane derivatives.
FeCl2 (10 mol%) 的使用允许苄基氯化锰 (II) 与各种芳基和杂芳基氯化物、溴化物和碘化物进行方便的铁催化交叉偶联反应,产生多官能化的二芳基和芳基杂芳基甲烷衍生物。
Versatile palladium-catalyzed arylation of organomanganese chlorides by aryl bromides
作者:Eric Riguet、Mouâd Alami、Gérard Cahiez
DOI:10.1016/s0022-328x(00)00891-3
日期:2001.4
In THF, a palladium-catalyzed cross-coupling reaction of organomanganese reagents with various aryl bromides including unreactive deactivated or hindered aryl bromides was performed successfully in the presence of a new catalytic system 1% PdCl2(dppp)-four equivalents DME. The scope of the reaction is very broad since many functional groups are tolerated, moreover, even hindered O,O ' -di- or trisubstituted diaryls were obtained in E;igh yields. It is interesting to note that hindered aryl bromides are more reactive than the corresponding aryl iodides. Alkyl, alkenyl and alkynylmanganese chlorides also react under similar conditions. (C) 2001 Elsevier Science B.V. All rights reserved.