Science of Synthesis

Schobert, R.; Gordon, G. J., Science of Synthesis, (2004) 27, 1001.

Triphenyl(vinyl)phosphonium salts are susceptible to attack from a range of nucleophiles. Nucleophilic addition to the β-carbon, followed by a double-bond shift generates phosphoranes, which undergo the Wittig reaction with carbonyl compounds. Alkyllithiums and organocuprates have been known for some time to add to vinylphosphonium salts giving ylides ‌55‌ (‌Scheme 19‌).[‌344‌] Triphenyl(vinyl)phosphonium bromide reacts with nucleophilic ω-carbonylanions forming various types of unsaturated carbo- and heterocycles (Section ‌27.24.2.2.4.5‌).[‌345‌–‌350‌] Deprotonated alcohols, amines, and sulfanyl compounds, when reacted with vinylphosphonium salts followed by treatment with an aldehyde, may be transformed into homoallylic ethers, amines, and thioethers.[‌351‌,‌352‌] Other examples include nucleophilic additions of dimethyl(phenylsilyl)lithium or tributylstannyllithium to the phosphonium salts yielding β-silyl- and β-stannylphosphorus ylides, respectively.[‌353‌] Sodium azide reacts in an unusual manner with substituted vinyl[‌354‌] and ethynyl[‌355‌,‌356‌] phosphonium salts resulting in the production of [5-aryltetrazol-1-yl)methylene]triphenylphosphoranes ‌56‌ and 5-aryl-4-(triphenylphosphoranylidene)-4H-1,2,3-triazoles ‌57‌, respectively (‌Scheme 19‌). Vinylphosphonium salts may be prepared by a proton shift from the more easily prepared allylic phosphonium salts using triethylamine[‌357‌] and sodium amide.[‌281‌]

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References

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• 8.Meeeee-Meee, (8888) M 8, 888.
• 8.Meeeee-Meee, (8888) M 8e, 888.
• 8.Meeeee-Meee, (8888) M 88e8, 888.