Nucleophilic Attack by Phosphorus

Reactions.—Nucleophilic Attack by Phosphorus. Alkyldichlorophosphines (3) undergo a mild Arbusov reaction with acid chlorides to give 

Sokal skii, and S. Z. Ivin, Zhur. obshchei Khim., 1970, 40, 701. 

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Nucleophilic Reactions of (Silylamino)phosphines. The reactions of (silylamino)phosphines with simple aldehydes and ketones proceed via nucleophilic attack by phosphorus followed by a [1,4] silyl migration from nitrogen to oxygen to yield new N-silylphosphinimines ( 3). With a,B-unsaturated carbonyl compounds, 1,4-addi-... 

Methyllithium attacked the sulfur atom of naphthothiete 205 to give 231 and oligomers 232 and 233 via 8-mercaptomethyl-l-lithionaphthalene. Treatment with lithium aluminum hydride followed by methylation gave 234. Treatment of thiete 215 with triphenylphosphine leads to ring-expanded products possibly via nucleophilic attack by phosphorus on sulfur. ... 

Interest in the Staudinger reaction of phosphines with azides, and the Mit-sunobu reaction involving nucleophilic attack by phosphorus at nitrogen in esters of diazodicarboxylic acids, has continued. Systems of the type (205) have been obtained from the reactions of secondary arylphosphines with azides. Treatment of these with butyllithium results in deprotonation to form the diaminophosphonium diazaylides (206). Phosphazenes have been prepared from azido-quinolines and -triazines, and also from diazoketones " and polycyanocyclopropanes. The Staudinger reaction has been employed in the synthesis of phosphorus-containing dendrimers, and in new approaches to amide and peptide synthesis. The reaction has also been used in a high-... 

Nucleophilic attack by phosphorus at sulphur is involved in the triphenylphosphine-induced cleavage of 1,2,4-thiadiazol-3-ones, in the reactions of methylideneaminophosphines with carbon disulphide, which gives the unstable four-membered ring system (81) as the initial product,and in the reaction with sulphur of the acetylenic phosphine (82) which results in the... 

These products, most easily explained as arising through nucleophilic attack by phosphorus on the carbonyl carbon followed by dealkylation of a phosphonium intermediate, are accompanied by varying amounts of a substance characterized as R C02C(R ) [P(0)(0R)2]2 by Kamai and Kukhtin (168). 

By contrast, cis- and trans-2-h itene episulfides react smoothly with this phosphorus reagent to give essentially quantitative yields of cis- and trans-2-huteneSj respectively. The stereospecific nature of this latter reaction rules out any mechanism involving nucleophilic attack by phosphorus on carbon to give intermediates 45 and 46. This path, which is favored for the comparable reactions of epoxides (286), would lead to the opposite stereochemical result. Direct abstraction of sulfur by phosphorus is favored by Neureiter and Bordwell (239,240). 

Once again, there has been considerable activity relating to the Mitsunobu and Staudinger reactions, in which nucleophilic attack by phosphorus at nitrogen is the initial step. The mechanistic complexity of the Mitsunobu reaction is confirmed following a further study of the various intermediates arising from the interaction of dialkyl azodicarboxylates with P(iii) compounds. Efforts have continued to effect improvements in S5mthetic applications of the Mitsunobu reaction, the main... 

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