Yu. Yu. Samitov

Reactions of ketoalcohols with organophosphorus compounds

1. n nThe reaction of diacetone andβ-acetoethyl alcohols with phenyldichlorophosphine was investigated by the NMR-P31 method. n n n n n2. n nThe previously proposed five-step scheme of interaction ofβ-ketoalcohols with dichlorides of trivalent phosphorus acids was confirmed.

Some new forms of the Arbuzov rearrangement

1. n ncis- and trans-3-Phosphonocrotonic triesters were synthesized by the addition of triethyl phosphite to tetrolic acid and by the action of 3-chlorocrotonic and 3-chloroisocrotonic esters on triethyl phosphite. n n n n n2. n nThe configurations of the phosphonocrotonic triester isomers were established by comparing the constants of these esters with the constants ofα andβ-phosdrin and by the analysis ofIR and PME spectra.

1,3-Dipolar cycloaddition of C-Benzoyl-N-phenyl- and C,N-diphenylnitrones to β-substituted vinylphosphonates

1. n nThe 1,3-dipolar cycloaddition of C,N-diphenyl- and C-benzoyl-N-phenylnitrones to diethyl β,β-diacetylvinylphosphonate yields trans-2,3-diphenyl-4-diethoxyphosphono-5-5-diacetylisoxazolidine and trans-2-phenyl-3-benzoyl-4-diethoxyphosphono-5,5-diacetylisoxazolidine, respectively. n n n n n2. n nC-Benzoyl-N-phenylnitrone reacts with diethyl β-phenylvinylphosphonate to form transtrans-2,5-diphenyl-3-benzoyl-4-diethoxyphosphonoisoxazolidine, and it reacts with dimethyl β-ethoxyvinylphosphonate to form trans-trans-2-phenyl-3-benzoyl-4-dimethoxyphosphono-5-ethoxy-isoxazolidine. n n n n n3. n nAs the electrophilic character of the double bond in the β-substituted vinylphosphonates is enhanced, their reactivity in 1,3-dipolar cycloaddition to nitrones increases.

Stereochemistry of organophosphorus compounds 15. Synthesis and permutational lability of 1,6,10-trioxa-8,8-dimethyl[(5-methoxy)-5-phosphaspiro(4.5)]dec-2-ene

1. n nWe have synthesized 1,6,10-trioxa-8,8-dimethyl[(5-methoxy)-5-phosphaspiro(4.5)]dec-2-ene, a compound in which the trigonal-bipyramidal phosphorus bond arrangment undergoes pseudorotation at temperatures below 36°C. Thermodynamic activation parameters for the pseudorotation process have been evaluated from the observed temperature variation of the parameters of the1H NMR spectrum. n n n n n2. n nThe enol acetate ofβ-neopentylglycolphosphonepropionic aldehyde has been prepared.

Stereochemistry of organophosphorus compounds: Communication 8. Configuration and conformational mobility of trans-2,3-diphenyl-4-dimethoxyphosphonoisoxazolidine ring

1. n nThe 1,3-bipolar cycloaddition of dimethyl vinylphosphonate to C,N-diphenylnitrone gave trans-2,3-diphenyl-4-dimethoxyphosphonoisoxazolidine, the structure and configurations of which were proved via the1H and31P NMR,1H -{31P} NMDR, and IR spectra. n n n n n2. n nFrom the stereospecificity of the vicinal spin-spin coupling constants3JPCCH and3JHCCH and the temperature dependence of the NMR spectra it follows that the isoxazolidine ring is found in the pseudorotation state.

Formation of steric isomers in reaction of limonene oxide with ethanol

1. n nThe reaction of limonene oxide with ethanol in both alkaline and acid media proceeds stereospecifically with the formation: a) in alkaline medium of (−)-2-hydroxy-1-ethoxy-trans-p-menth-8-ene and the steric isomers of (−)-1-hydroxy-2-ethoxy-trans-p-menth-8-ene and (+)-1-hydroxy-2-ethoxy-cis-p-menth-8-ene; b) in acid medium of (−)-1-hydroxy-2-ethoxy-trans-p-menth-8-ene and the steric isomers of (−)-2-hydroxy-1-ethoxy-trans-p-menth-8-ene and (+)-2-hydroxy-1-ethoxy-cis-p-menth-8-ene. The isomerization products of limonene oxide: dihydrocarvone, trans-carveol and trans-isocarveol, are also formed in alkaline medium. n n n n n2. n nThe NMR method was used to study the conformation of the obtained addition products of ethanol to limonene oxide.

Synthesis and structure of 1-oxo-1-chlorophospholenes

1. n nThe interaction of divinyl with butyldichlorophosphite and a mixture of butyldichlorophosphite and phosphorus trichloride was studied. n n n n n2. n nIn the first case one isomer is formed (phospholene-3), while in the second a mixture of isomers is produced (phospholene-2 and phospholene-3).

1,3 Dipolar cycloaddition of C-benzoyl-N-phenylnitrone to esters of vinyl-, β-cyanovinyl, and allylphosphosphonic acids and of C,N-diphenylnitrone to an allylphosphonic acid ester

1. n nThe reaction of 1,3 dipolar cycloaddition of C-benzoyl-N-phenylnitrone to dimethyl vinylphosphonate at 20° gave isomeric trans-2-phenyl-3-benzoyl-4-dimethylphosphono- and trans-2-phenyl-3-benzoyl-5-dimethylphosphonoixoxazolidines. Only the first isomer is obtained in the reaction in boiling benzene. n n n n n2. n nThe 1,3 dipolar addition of C-benzoyl-N-phenylnitrone to the diethyl ester of β-cyanovinylphosphonic acid leads to trans-2-phenyl-3-benzoyl-4-diethylphosphono-5-cyanoisoxazolidine. n n n n n3. n nThe cycloaddition of C,N-diphenylnitrone to the dimethyl ester of allylphosphonic acid leads to the formation of trans-2,3-diphenyl-5-dimethylphosphonomethyleneisoxazolidine, while the cycloaddition of C-benzoyl-N-phenylnitrone to this diester gives trans-2-phenyl-3-benzoyl-5-dimethylphosphonomethyleneisoxazolidine.

Stereochemistry of organophosphorus compounds Communication 9. Study of the NMR-1H and32P method of the configuration and conformation of cyclic phosphites based on dimethyl esters of D- and mesotartaric acids

1. n nTrans- and cis-orientations of the carbomethoxyl substituents at the C4 and C5 atoms in 1,3,2-dioxaphospholanes, synthesized on the basis of esters of D- and mesotartaric acids, respectively, were confirmed. n n n n n2. n nConformation lability of the five-membered heterocycle of the compounds studied was demonstrated in the interval from −80 to 28°; on the basis of the vicinal spin-spin interaction constants3JPOCH and3JHCCH and their temperature dependence, conclusions were drawn on the most probable conformations, among which the pseudoconversion chiefly occurs. n n n n n3. n nOn the basis of the heteronuclear Overhauser effect1H-{31P} and the paramagnetic shifts induced by Eu(DPM)3 and the aromatic solvent, information was obtained in support of a pseudoaxial arrangement of the substituents at the phosphorus atom.

Steric structure of 5-substituted 2,2-dimethyl-1,3,2-dioxasilanes

1. n nThe structure of 5-substituted 2,2-dimethyl-1,3,2-dioxasilanes was studied by the methods of dipole moments and PMR spectroscopy. The compounds have a predominant chair conformation. n n n n n2. n nIn the case of 2,2-dimethyl- and 2,2,5-trimethyl-5-nitro-1,3,2-dioxasilane, a conformational equilibrium can exist, strongly shifted in the direction of the conformation with an axial nitro group.