Witting reaction

The Witting reaction has been investigated in aqueous conditions.305 Wittig olefination reactions with stabilized ylides (known as the Wittig-Homer or Homer-Wadsworth-Emmons reaction) are sometimes performed in an organic/water biphase system.306 Very often, a phase-transfer catalyst is used. Recently, the use of water alone as solvent... 

Bestmann, H. J., Vostrowsky, O. Selected Topics of the Witting Reaction in the Synthesis of Natural Products. 109, 85-163 (1983). 

Microwave-assisted regiospecific shyntesis of 2-trifluoromethyl-7-trihalomethylated pyrazolo[l,5-a]pyrimidines has been reported <06MI358>. A one-step synthesis of pyrazolo[ 1,5-a]pyrimidine via an intermolecular aza-Witting reaction has been achieved <06JHC523>. 

A Witting Reaction on a coordinated C02 unit forms a metal ketene complex105 according to ... 

A ketone or aldehyde is converted into an alkene by means of the Wit reaction. In this process, a phosphorus ylide, (also calledj... 

As described here, 2 can be prepared in two steps from commercially available D-gluco e in up to 65% overall yield. Procedures to obtain the ethylidene glucose1012 and the ensuing oxidative degradation8-512-16 are based on earlier literature reports. The D-erythrose acetal 2 has also been prepared from D-mannitol in three steps, with an overall yield of 7%.17 The erythritol 4 can be synthesized from 2 by reduction with sodium borohydride 8 A mixture of Z/E-3 (ca. 2 1) is known to result from a Witting reaction of 2 with ethoxycarbonylmethylenetriphenylphosphorane 2a,6,7... 

Horner-Witting reaction of the succinate (197) with 4-formylpyrimidine led to ethyl 8-oxo-8i/-pyrido[l,2-c]pyrimidine-6-carboxylate (80LA542). 

Removal of phosphorus with formation of a C=C bond (Witting reaction) 997... 

The product of a reaction of chloromethylated polystyrene and triphenylphosphine can also convert to nucleophiles. In addition, use of a phase transfer catalyst converts soluble chloromethylated polystyrenes to phosphine oxides. Reactions with dioctylphosphine can serve as an example. Sometimes, phase transfer reactions are easier to carry out than conventional ones. This is the case with a Witting reaction. Both linear and crosslinked chloromethylated polystyrenes react smoothly with triphenylphosphine to give derivatives that react with various aldehydes. Phase transfer catalysts can also be used in carrying out nucleophilic substitutions with the aid of sulfides, like tetrahydrothiophine... 

A special case is the use of the Witting reaction. Poly(p-phenylene pentadienylene)" ... 

A special case is the use of the Witting reaction. Poly(p-phenylene pentadienylene) [415] is prepared by this reaction first. This is utilized in a preparation of a block copolymer [456] according to the... 

Poly(phenyl vinylene) can be synthesized by several routes. One of them is step growth polymerization [80] by the Witting reaction ... 

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