Synthesis and Characterisation of Phosphonium Ylides

Ylides containing fluorine atoms are of obvious utility, considering the importance of fluorine-containing compounds and materials. Kolodiazhnyi and Schmutzler have reviewed the synthesis, properties and applications of ylides 

Other new ylides that have been reported recently include (53), which is useful for the conversion of aldehydes into Y,b-unsaturated allyl p-ketoesters, and (54), 

The triflic acid-promoted hydrolysis of bis-triphenylphosphonio-isophos-phindolide cation (38) has been followed using NMR spectroscopy. No evidence was found for direct phosphorus protonation or alkylation which had previously been postulated. 

Hanamoto and co-workers have published a detailed report on the synthesis and reactivity of a-fluorovinylphosphonium salt (39), which they had first described in a previous communication. Ylides derived from (39) have been 

Cheng and co-workers have reported a unique method for the synthesis of fullerene derivatives of ylides (45) from the reaction of C o with tertiary phosphines and electron deficient acetylenes. All four new ylides show temperature dependent NMR spectra that can be rationalised on the basis of the interchange between two E, Z isomers. The structure of compound (45a) was determined crystallographically. 

Other ylides which have been reported include (46), which undergoes 

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The Synthesis and Characterisation of Phosphonium Ylides. - Bertrand and co-workers have reported the instantaneous quantitative formation of phosphorus ylides (15) when stable phosphanylcarbenes are treated with phosphines (Scheme 1). Ylides (15) are very readily oxidised by atmospheric... 

Synthesis and Characterisation of Phosphonium Ylides. - We start this section with a phosphanylidene-o -phosphorane (14) which, although not strictly an ylide, has a P-P bond which displays many of the properties of more conventional phosphonium ylides. A crystal structure of (14) revealed a P-P bond length of 2.084(2) A, which is similar to those found in other phos-phanylidene-o( -phosphoranes and is certainly shorter than a typical P-P single bond ca. 2.22 A), indicative of multiple bond character. Compound (14) undergoes reactions with electrophiles (Scheme 1) which demonstrate its nucleophilic... 

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