Phosphabicyclo octanes

A value of 0.91 D has been calculated for the free electron-pair moment in P compounds, using dipole-moment data for P4S3 and the phosphabicyclo-octane derivative (110). Calculations for the compounds in the series PH Me3 with n - 0—3 point to variation in the free electron-pair moment as being the most important factor in determining the observed dipole moments extension to a variety of other species allows the calculation of new values for the moments of typical bonds to phosphorus. 

Ozoe et al.76 have determined the Kd values for complexes of ot- and fl-cyclo-dextrin with a variety of 4-substituted bicyclic phosphates (4-substituted 2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane 1-oxides, 1), which are highly toxic convulsants. 

Scheme 54 Synthesis of (2/t,55)-l,3-diaza-2-chloro-3-phenyl-2-phosphabicyclo[3.3.0]octane 198...

Almost diastereomerically pure (2i ,55)-l,3-diaza-2-methoxy-3-alkyl-2-phosphabicyclo[3.3.0]octanes (201a-d) were formed in the reaction of (S)-2-anilinomethyl)-pyrrolidines (197b-e) with methyl dichlorophosphite in the presence of NEt3 (Scheme 55) [86], With these ligands, high stereoselectivity (ee s up to 91%) was observed in the Pd catalyzed ally lie animation reaction [86],... 

Diastereomerically pure (2W,5.V)-l,3-diaza-2-(2-methylphenyl)-3-phenyl-2-phosphabicyclo[3.3.0]octane (.S )-202] was formed in the thermal reaction of (S)-2-(anilinomethyl)pyrrolidines (197a) with o-TolP(NMe2)2 and isolated in 27% yield after recrystallization (Scheme 56) [87], Its cyclopalladation with palladium diacetate followed by anion metathesis gave dimer (5,5)-203 (Scheme 56) [87],... 

A useful method for large-scale synthesis of diastereomerically pure (2R,5S)-3 -phenyl-2-(8-quinolinoxy)-1,3-diaza-2-phosphabicyclo[3.3.0]octane (205) was based on a similar reaction of tris(dimethylamino)phosphine with (5)-197a generating the intermediate 204 which, by addition of 8-hydoxyquinoline followed by additional refluxing gave the final product. Recrystallization of the crude reaction mixture afforded diastereomerically pure 205 as a solid, stable to air and moisture in 98% yield (Scheme 57) [88], It was converted to complex 206 by mixing with... 

The parent compound, 69, has been synthesized and characterised <2003ZFA1475>. 4-Chloro-hepta-l,6-diene was reacted with Mg. No Grignard rearrangement was noticed but instead the Grignard reagent was converted into l-allyl-3-butenylphosphonous dichloride by reaction with PC13. Reduction with LiAlH. produced l-allyl-3-butenyl-phosphane. Radical-initiated cyclization led to the product, l-phosphabicyclo[3.3.0]octane. Four derivatives were similarly prepared and characterized (70-73). Compound 74 was similarly prepared via a radical reaction < 1997PS(123)141 >. 

Cooper, G.H., I.W. Lawston, R.L. Rickard, and T.D. Inch. "Structure-Activity Relations in 2,6,7-Trio xa-l-phosphabicyclo[2.2.2]octanes and Related Compounds." European Journal of Medicinal Chemistry 13 (1978) 207-212. 

Ethyl-2,6,7-trioxa-l -phosphabicyclo [2.2.2] octane 1 -Oxide C06-A002... 

Isopropyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane 1-Oxide C06-A003... 

Scheme 25). l-Oxo-2,8-diphenyl-2,5,8 triaza-1 X -phosphabicyclo[3.3.0]octane (68) formed by acid catalysis of the bicyclic phosphoric triamide (67) has been found to isomerize via a new type of rearrangement to yield the ring contracted 3-[2-(phenylamino)ethyl]-2-oxo-2-ethoxy-l-phenyl-l,3,2 A, -diazaphospholidine (69). The rearrangement has been explained in terms of intramolecular 1,5-nucleophilic attack... 

Tanaka and have independently developed effective protocols for the catalytic cyclization/borylsilylation of diynes to form bis(functionalized) dialkylidene cyclopentanes. As an example of the Tanaka procedure, reaction of 1,6-heptadiyne with borylsilane 99 catalyzed by a 1 2 mixture of Pd2(DBA)3 and ETPO (ETPO = 4-ethyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane) at 110°G for 2h gave 100 in 81% yield (Equation (64)). As an example of the Ito procedure, reaction of 1,7-octadiyne with dimethylphenylsilylpinacolborane, catalyzed by the Ni(0) complex generated in situ from a 1 2 2 mixture of Ni(acac)2, DIBAL-H, and P(/ -Bu)3 in toluene at 110°C, gave the bis(functionalized) dialkylidene cyclohexane 101 in 55% yield (Equation (65)). " Tanaka s protocol was also effective for the cyclization/borylsilylation of 1,6-enynes. As an example, reaction of dimethyl allylpropargylmalonate with 99 catalyzed by Pd2(DBA)3/ETPO gave the bis(functionalized) alkylidene cyclopentane 102 in 84% yield with exclusive delivery of the borane to the alkyne moiety of the enyne (Equation (66)). ... 

One example performed in this laboratory is the analysis of toxicity exerted by bicyclic phosphate esters 26). 2,6,7-Trioxa-l-phosphabicyclo[2.2.2]octane-l-oxides (IS) with suitable 4-substituents (R) are highly toxic to mammals 27). The 4-Et derivative... 

Phosphabicyclo-[2.2.1]heptane and -[2.2.2]octane 1-oxides can be prepared by the reaction of branched tribromides with triethyl phosphite by an Arbusov reaction, followed by a Grignard reaction in the presence of Mg in THF when the carbon-phosphorus rings are closed (equation (11)). When the JH and 13CNMR data were studied certain very large... 

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