Phosphorochloridites cyclic

Cyclic phosphorochloridites are reported to undergo rapid inversion at phosphorus. This has now been shown to depend on the purity of the sample, and pure samples, which show high barriers to inversion, have been obtained. ... 

A successful synthesis (Scheme 19) of the phosphonic acid analogues of D-and L-penicillamine commences with the cyclic phosphorochloridite (132). Other attempts using (132 ... 

The aminosugar was allowed to react with phosphorus trichloride to give the intermediate cyclic phosphorochloridite (step a). The latter was trans-... 

The first example of the asymmetric synthesis of P-chiral trialkyl phosphates (12) via trialkyl phosphite, in which the keystone is dynamic kinetic resolution in the condensation of a dialkyl phosphorochloridite (13) and an alcohol by the catalytic assistance of a chiral amine has been reported (Figure 2)." 2,4-Dinitrophenol (DNP) was employed as an activating reagent with ben-zyloxy-bis-(diisopropylamino) phosphite to synthesize the cyclic phosphate derivatives (14) from a series of alkane diols HO-(CH2)n-OH (n=2-6). Included was a cyclic phosphate derivative of carbohydrate (15). The mechanism of activation by 2,4-DNP and cyclization was also described (Figure 3). ... 

Conversion of alcohols to iodides,2 An alcohol, for example cyclohexanol (1), is treated in ether solution with the cyclic phosphorochloridite (2) in the presence of pyridine to form the phosphite (3), which on treatment with iodine gives the... 

Other reactions between cyclic phosphorochloridites or cyclic esters and dienes are summarized in Scheme here, A and B are O, S or Se, and may be different or identical, and X = Cl, Br, NCS, or OR, and the conversion is brought about when mixtures of reactants are heated together in sealed tubes for extended time periods. As in the many examples known in which the reacting system, as a whole, is sulphur-free, the nature of the intermediate can be in doubt, and probably depends on the nature of the substituents, particularly those directly connected to phosphorus thus some reactants may interact through a covalent, pentacoordinate species 27, whereas others form a pseudoquatemary intermediate 28. It may also be that one intermediate structure is transformed into the second before the ultimate formation of the 3-phospholene (29). Also, in accord with these ideas, thiophosphorus(III) halides have been obseved to react with a,j5-unsaturated ketones to give, ultimately, l,2-oxa-4-phospholenes as their 2-sulphides (30) (Scheme 3)45 8. reactions carried out in acetic acid solution the products are said to be the esters... 

The reaction between cyclic ketone enolates and diethyl phosphorochloridite followed by aerial oxidation of the intermediate P(III) esters, yields mixtures of C - and (7-phosphorylated products. The formation of the (1 -oxoalkyl)phosphonic diesters was optimized using diethyl ether as solvent (although better yields were sometimes obtained for reactions in Et20/THF when hexamethylphosphoric triamide was added) when the... 

Dialkyl thiophosphites from phosphorochloridites (ROjaPGl (ROjaPSH s. 16, 632 cyclic compounds s. R. S. Edmundson, Ghem. Ind, 1965, 1220... 

Without additional reagents Cyclic phosphorochloridates from cyclic phosphorochloridites... 

There are several procedures for conversion of alcohols to iodides which are based on alkoxyphosphonium intermediates. One involves preparation of a cyclic phosphite ester from the alcohol and o-phenylene phosphorochloridite. Treatment of the cyclic phosphite ester with iodine then generates the alkyl iodide ... 

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