Tricyclic phosphite

Finally, new tricyclic hexacoordinated phosphoranes with internal P-N coordination were synthesized by Swamy and coworkers by oxidative addition of cyclic phosphite precursors with quinones or with a combination of diols and (z-Pr)2NCl [57, 58]. Various ring sizes from five to eight membered were obtained showing the generality of the approach. A selection of compounds (47a-47e) is presented in Fig. 8. 

The susceptibility of phosphites to hydrolysis limits their application as ligands for homogeneous catalysis. The fused tricyclic monophosphites derived from ca 1 i x[4]arenes260-262 form coordination complexes with palladium.263... 

The vicinal diol of the monoterpene series, (15,2S,3/ ,5S)-(+)-2,6,6-trimethylbicyclo [3.1.1]heptane-2,3-diol (1), was converted upon reaction with methyl dichloro-phosphite into a tricyclic phosphite 2 showing a 95 5 ratio of epimers differing at the phosphorus stereocentre (Scheme 1). Its complexes with Rh(I) and Pd(II) were found to have the structures (u-Cl)2[Rh(CO)L, and ris-CL,PdL2 respectively [16]. 

Trioxa-l Phosphaadamantane (L). The tricyclic phosphite was prepared by a method described previously 16). 

During reduction of the nitro derivatives 261 (with stannous chloride in hydrochloric acid, - with hydrogen over Raney nickel in ethanol, with iron powder in 50% acetic acid, - or with triethyl phosphite - at 170-1 SOX), the resulting amino derivatives 262 sometimes underwent spontaneous cyclization and gave the linearly annelated tricyclic compounds 263. Cyclization of the amino derivatives 262 was effected ther-mally or by the action of phosphoryl chloride. - ... 

Reductive cyclization of the nitro-thienylideneaniline (33.1) (a masked nitro-aldehyde) with triethyl phosphite gives low yields of the tricyclic pyrazole but higher yields may be obtainable from the azides (Chapter S9, Section 1.2). 

The synthesis, structure, and reactivity of phospha(m)adamantanes and tricyclic analogues have been reviewed. The basicity of the amino groups in some aminophosphines have been estimated by i.r. measurements. An Arbuzov reaction between trimethyl phosphite and an iodo-cobalt complex has been studied by H and P n.m.r. ... 

Treatment of N-2,4-dinitrophenylpyridinium chloride (778) with phenyl-hydrazine in acetic acid causes reductive cyclization to yield the pyrido[l,2-ajimidazole (779). 3-Aminocrotononitrile, MeC(NH2)=CHCN, condenses with quinoline 1-oxide and isoquinoline 2-oxide to form the tricyclic compounds (780) and (781), respectively." The imidazo[5,l-a]isoquinoline derivative (783) is obtained by the action of phenyl isothiocyanate on the sodium salt of the Reissert compound (782)." ° Triethyl phosphite reduces the o-nitrophenyldipyr-rolylmethane (784 R=N02) to the nitrene (784 R = N), which forms the pyrrolo[3,2-6]quinoline derivative (785) by an intramolecular insertion reac-tion." 3-Amino-177-isoindole (786) reacts with acetylacetone in the presence of perchloric acid to yield the pyrimidoisoindolium salt (787). ... 

The reaction product of ribitol and phosphorus trichloride in the presence of triethylamine has been re-examined and shown to be the tricyclic phosphite (42). 1,2-0-Isopropylidene-D-glucuronic... 

The benzoylphosphonate (168) underwent cyclisation and deoxygenation in the presence of excess trimethyl phosphite to give the corresponding benzofuran (170). ° The reaction pathway involved the phosphite attack on the initially formed, tricyclic dioxaphospholane intermediate (169) with the subsequent loss of two molecules of trimethyl phosphite. In the absence of the additional molecule of P(OMe)3, the initially formed (169) underwent a loss of trimethyl phosphite and a subsequent rearrangement to the p-ketophosphonate (171) (Scheme 59). 

Alkylidene-a-D-glucofiiranose 3,4,5-bicyclic phosphites (47) have been ozonized to the corresponding tricyclic phosphates (48). Hydrolysis of compound (48, Z = CMCj), followed by esterification, furnished the monocyclic pho hate products (49). °... 

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