Tributylgermanium hydride as a replacement for tributyltin hydride in radical reactionsElectronic supplementary information (ESI) available: full experimental details and data. See http://www.rsc.org/suppdata/ob/b3/b310520b/
作者:W. Russell Bowman、Sussie L. Krintel、Mark B. Schilling
DOI:10.1039/b310520b
日期:——
Tributylgermanium hydride (Bu(3)GeH) can be used as an alternative to tributyltinhydride (Bu(3)SnH) as a radical generating reagent with a wide range of radical substrates. Tributylgermanium hydride has several practical advantages over tributyltinhydride, e.g. low toxicity, good stability and much easier work-up of reactions. The reagent can be easily prepared in good yield and stored indefinitely
We have prepared highly efficient radical probes 2a-b involving the hex-5-enyl rearrangement. The reaction of 2a-b with active magnesium leads to the cyclized products 4a-b, providing a direct evidence of radical intermediates during the formation of aryl Grignardreagents. The variations of yields for cyclized products 4a-b as a function of structural modifications in 2a-b suggest that the intervention
Observations on the intramolecular Heck reactions of aromatic chlorides using palladium/imidazolium salts
作者:Stephen Caddick、William Kofie
DOI:10.1016/s0040-4039(02)02340-7
日期:2002.12
The intramolecular Heck reaction of aromatic amines and ethers using palladium/imidazoliumsalts is described. The use of tetra-n-butylammonium halide salts facilitates the reactivity of aromatic chlorides. An unexpected and novel palladium-mediated cyclisation is also described leading to the formation of a tricyclic adduct.
Titanocene-Catalyzed Regioselective Carbomagnesation of Alkenes and Dienes
作者:Shinsuke Nii、Jun Terao、Nobuaki Kambe
DOI:10.1021/jo0354241
日期:2004.1.1
the use of a titanocene catalyst. This reaction proceeds efficiently at 0 °C in THF in the presence of Cp2TiCl2 by the combined use of organichalides (R−X; R = alkyl, aryl and vinyl) and n-BuMgCl to afford benzyl, α-silylalkyl, or allyl Grignardreagents, which were trapped with various electrophiles. The present reaction involves (i) addition of carbon radicals toward alkenes or dienes in the carbon−carbon
通过使用钛茂催化剂,已经开发了一种用于烯烃和二烯的区域选择性碳还原的新方法。通过有机卤化物(RX ; R =烷基,芳基和乙烯基)和n- BuMgCl的组合使用,该反应在0°C的Cp 2 TiCl 2存在下于THF中有效进行,得到苄基,α-甲硅烷基烷基,或烯丙基格氏试剂,它们被各种亲电试剂捕获。本反应包括(i)在形成碳-碳键的步骤中向烯烃或二烯添加碳自由基,以及(ii)在Ti-上进行苄基-,α-甲硅烷基烷基-或烯丙基噻吩茂金属上的正金属化,并在碳-镁键形成步骤。该反应的范围和局限性也已被研究。
How the by-products hint at mechanisms and suggest new synthetic routes in some organolithium reactions
作者:Norma Sbarbati Nudelman、Graciela V. García、Susana Velurtas
DOI:10.1002/poc.575
日期:2002.12
that the reaction proceeds through an open lithiated intermediate. In another study, radicals of benzil were generated on the lithium surface and their reactions studied in THF. Characterization of the minor products, the rates of decay of the reagent and formation of products, and also periodical EPR of the reaction mixture, allowed the proposal of the whole reaction mechanism. In both reactions studied