Ironing out the kinks: Efficientnew catalytic systems based on iron thiolates are described for the iron‐catalyzed cross‐coupling of alkyl Grignard reagents with alkenylhalides (see scheme). The reaction is highly chemo‐ and stereoselective. With this new procedure, the use of N‐methylpyrrolidone as a co‐solvent is no longer required.
A new robust methodology for gram-scale iron-catalyzed cross-coupling between alkyl Grignard reagents and alkenyl or aryl halides is developed. This method does not require toxic additives such as NMP or expensive ligands. Its efficiency relies on the use of simple alkoxide magnesium salts as additives. On the basis of these results, a new procedure for one-pot synthesis of substituted benzamides from
Cobalt-catalyzed alkenylation of organomagnesium reagents
作者:Gérard Cahiez、Hovsep Avedissian
DOI:10.1016/s0040-4039(98)01266-0
日期:1998.8
Alkenyl iodides, bromides and chlorides react with organomagnesium reagents in THF, in the presence of Co(acac)2 and NMP (9 to 4 equiv.), to give the cross-coupling products in good yields. The reaction is chemoselective (aryl or alkyl bromides, esters and ketones) and stereoselective (≥99.5%).
Chalcogen electrophile induced rearrangement of 1-alkynyltrialkyl borates: controlled syntheses of trisubstituted olefins from 1-alkynes
作者:Julien Gerard、László Hevesi
DOI:10.1016/s0040-4020(01)00904-8
日期:2001.10
The reaction of 1-alkynyltrialkyl borates with sulfenyl, selenenyl and tellurenyl halides produces β-chalcogeno alkenylboranes in good yields, with a cis relationship between the boron and the chalcogen moities. Protodeborylation of these compounds by acetic acid, or by a transmetalation–protonolysis sequence, leads to vinyl chalcogenides, which can be converted to alkenes by means of a nickel catalyzed
Iron-Catalyzed Alkenylation of Grignard Reagents by Enol Phosphates
作者:Gérard Cahiez、Olivier Gager、Vanessa Habiak
DOI:10.1055/s-2008-1067194
日期:2008.8
Stereoselective preparation of trisubstituted olefins can be easily performed from an Z/E-mixture of enol phosphates by reacting only the E-isomer with a Grignardreagent in the presence of Fe(acac) 3 . This procedure combines a kinetic differentiation and a stereoselective reaction. The coupling is very chemoselective in the presence of an alkyl chloride, an ester, a ketone or a nitrile.