Addition of tertiary phosphines and phosphites

Olefins with electrophilic substituents, but not those with electron-donating substituents, add tertiary phosphines 61 the phosphonium betaines first formed stabilize themselves under some circumstanes by forming their tautomers, the alkylidenephosphoranes. Thus, for example, the ylide (5) is obtained in more 

Arbuzov and co-workers, Izv. Akad. Nauk SSSR, Otd. Khim. Nauk. 1962, 2074 Chem. Abstr., 58, 11396 0963). 

Quinones also add tertiary phosphines, but give partly C- and partly 0-phos-phonium compounds.63 A series of phosphonium bromides has been prepared in high yields by warming triphenylphosphine with activated olefins such as acrylic acid derivatives in 48% hydrobromic acid at 100° 64 

Electronegatively substituted acetylenes afford triphenylvinylphosphonium salts analogously in high yields but under somewhat more energetic conditions.65 In the absence of acid the primary adducts of aromatic phosphines to acetylenes readily undergo further reactions.66,67 

When trialkyl phosphites are heated with acrylic acids to about 120° [2-(alkoxycarbonyl)ethyl]phosphinic esters are formed, sometimes in satisfactory yield 68 

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