T. A. Zyablikova

Study of equilibrium of 5-phenyl-2,4,6-trimethyl-1,3,5-dioxaphosphorinane stereoisomers and their derivatives

We determined the conformational free energy of a phenyl substituent on a tri- and tetracoordinated phosphorus atom in a 2,4,6-trimethyl-1,3,5-dioxaphosphorinane ring.

Orientation of phenyl group attached to phosphorus atom in 5-phenyl-1,3-di-R-1,3,5-diazaphosphorinanes

Conclusions1.The phenyl group in 5-phenyl-1, 3-di-R-1, 3,5-diazaphosphorinanes exists preferentially in an equatorial orientation.2.An analogy is observed in the change in the conformational free energy of the substituent attached to the carbon and phosphorus atoms when the ring CH2 groups are substituted by oxygen or nitrogen atoms.

Spatial structure of the stereoisomers of 5-phenyl-5-oxo-2,4,6-trimethyl-1,3,5-dioxaphosphorinane

Conclusions1.The stereoisomers of 5-phenyl-5-oxo-2,4,6-trimethyl-1,3,5-dioxaphosphorinane have been obtained.2.The stereoisomers obtained have equatorial CH3 groups and differ with respect to the orientation of the P=O bond.3.The stereoisomer with the equatorial orientation of the P=O bond predominates at equilibrium.

Three-dimensional structure of 5-phenyl-5-seleno-1,3,5-dioxa- and 5-phenyl-5-seleno-1,3,5-diazaphosphorinanes

Conclusions1.Substituted 5-phenyl-5-seleno-1,3,5-dioxaphosphorinanes exist as stereoisomers that differ in the orientation of substituents at the P and C atoms. In the case of 5-phenyl-5-seleno-2,4,6-trimethyl-l,3,5-di-oxaphosphorinane, the thermodynamically stable stereoisomer is the one in the chain conformation with an axial phenyl at the phosphorus atom.2.5-Phenyl-5-seleno-l,3,5-diazaphosphorinanes are mixtures of conformers that differ in the orientation of the phenyl at the phosphorus atom.

Twist form in equilibrium of stereoisomers of 5-phenyl-2,4,6-triisopropyl-1,3,5-dioxaphosphorinane and its derivatives

ConclusionsIn the equilibrium of 5-phenyl-2,4,6-triisopropyl-1,3,5-dioxaphosphorinane and its derivatives the stereoisomer with nonequivalent protons on the carbon atoms attached to phosphorus is found predominantly in the twist form.

Influence of nickel and cobalt acetylacetonates on the NMR spectra of substituted 1,3,5-dioxaphosphorinanes

Conclusions1.On the basis of1H and31P NMR data, derivatives of the 1,3,5-dioxaphosphorinanes have predominantly the chair conformation. In low-boiling isomers, the orientation of unshared electron pairs and P=O and P=S groups is equatorial, and in high-boiling isomers is axial.2.The region of most probable values of the geminal SSCC2JPH has been determined as a function of orientation of the P=O and P=S groups.3.Structures of the complexes Ni(acac)2 and Co(acac)2 with derivatives of 1,3,5-dioxaphosphorinanes have been studied.4.Linear correlation of values of2JPH in the diamagnetic state and hfs constants of the protons in a paramagnetic complex has been established.

Equilibrium of stereoisomers of 2,4,5,6-tetraphenyl-1,3,5-dioxaphosphorinane and its derivatives

ConclusionsThe stereoisomers with an equatorial orientation of the phenyls on the phosphorus atom and on the carbon atoms of the ring predominate in the equilibrium of 2,4,5,6-tetraphenyl-1,3,5-dioxaphosphorinane, its oxide, and its sulfide.

The synthesis and three-dimensional structure of 2,5-diphenyl-2-bora-1,3,5-dioxaphosphorinane

ConclusionsHydroxymethyldiphenylboryloxymethylphenylphosphine and 2,5-diphenyl-2-bora-1,3,5-di-oxaphosphorinane, in which the phenyl group at the phosphorus atom is predominantly found in the axial position, are formed in the reaction of di(hydroxymethyl)phenylphosphine with isobutyl diphenylborate.