Phosphonic diamides cyclic

Aromatic isocyanates, particularly those containing electron-attracting substituents, react noticeably more easily than aliphatic isocyanates. In the former case it often suffices to leave the components for some hours at room temperature in a water-pump vacuum, whereas for aliphatic compounds boiling under reflux is usually necessary and sometimes use of a higher-boiling solvent such as decalin. The best catalysts are cyclic phosphine oxides of type (1) (phospholene oxides)862 and cyclic phosphonic diamides of type (2) (1,3,2-diazaphospholidine oxides).863 The best results were obtained with compound (1, R = C2H5) (for its preparation see Campbell et a/.862) the phenyl compound, although more readily prepared,864 is somewhat less reactive. The amounts of catalyst needed are 0.1% for (1) or 0.5% for (2). 

A similar cheletropic condensation occurs between a phosphenium cation and a hydra-zone from crotonaldehyde (equation 27) to give a cyclic phosphonic diamide derivative. ... 

A long and detailed theoretical analysis of the behaviour of the lithiated anions from both cyclic and acylic phosphonic diamides has recently been presented, and their reactivity has been discussed in terms of relative conformations of nitrogen lone electron pairs, phosphoryl bonding and anionic charge ... 

Thio analogs of these compounds, for example, PhP(S)(NHR)2 can also be prepared similarly, from the corresponding thiophosphonic halides and amines or by oxidative addition of sulfur to diaminophosphines, RP(NR92 Phenylphosphonic acid diamides, PhP(Q)(NHBu )2 (Q = S, Se) were prepared from PhP(NHBfr)2 by oxidative addition of sulfur or selenium and the 0x0 derivative PhP(0)(NHBu )2 by oxidation with tert-butyl peroxide. Their lithiation produces unusual cyclic or polycyclic dUithium salts of the phosphonate dianions [PhP(Q)(NBfr)2] (Q = O, S, Se). The dimethylaluminum derivatives PhP(Q)(NBu )2AlMe2 (Q = S, Se) obtained from PhP(Q)(NHBu )2 with AlMes are fom-membered chelate rings. ... 

The classical reaction between a (haloalkyl)phosphonic diester and NaN3, best carried out in a polar solvent, e.g dmf has been developed into an asymmetric synthesis. The reaction between (chloromethyl)phosphonic dichloride and the chiral auxiliary (5)-(phenylaminomethyl)pyrrolidine (314) is followed by separation of the product 1,3,2-diazaphosph(V)olidines 315 (R = H X = Cl) and 316 (R = H X = Cl), obtained in yields of 36 and 45%. Alkylation (BuLi, RX) of the cyclic diamides and reaction between the products and NaN3, to give 315 and 316 (R = alkyl X = N3), is then followed by acidoly-... 

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