L. M. Burnaeva

A New Approach to The Synthesis of Phosphoranes Based on the Reaction of Benzo[d]-1,3,2-Dioxaphospholes, Having β- or γ-Unsaturated Group in a Substituent, with Compounds Containing Multiple Bonds

We developed a new approach to the synthesis of phosphoranes and carba phosphatranes on the basis of the reaction of benzo[d]-1,3,2-dioxaphospholes, having β- or γ-unsaturated group in a substituent, with such compounds containing multiple bonds, such as hexafluoroacetone, chloral, and diethylacetylenedicarboxylate.

Reaction of 2-methoxy-1,3,2-dioxaphosphorino[4,5-b]pyridin-4(4H)-one with hexafluoroacetone

The reaction of the di-O-trimethylsilyl derivative of 2-hydroxynicotinic acid with methyl phosphodichloridite afforded 2-methoxy-1,3,2-dioxaphosphorino[4,5-b]pyridin-4(4H )-one. The NMR spectrkscopic data suggest that the reaction of the latter with hexafluoroacetone produces unstable 2-methoxy-2,5-dioxo-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-dioxaphosphepino[4,5-b]pyridine, which is readily transformed into 9-methyl-2,5-dioxo-4,4- bis(trifluoromethyl)-4,5-dihydro-1,3,2-dioxaphosphepino[4,5-b]pyrid-9-inium-2-oate. The structure of the hydrolysis product of the latter, viz., 1-methyl-3-(2-hydroxy-3,3,3-trifluoro-2- trifluoromethylpropanoyl)pyridin-2-one, was established by X-ray diffraction analysis.

Peculiar Features of Reaction of 2-tert-Butoxy-5,6-benzo-1,3,2-dioxaphosphinin-4-one with Chloral. Steric Structure of 2-Chloro-3-trichloromethyl-6,7-benzo-1,4,2λ5-dioxaphopshepin-5-one 2-Oxide

The reaction of 2-tert-butoxy-5,6-benzo-1,3,2-dioxaphosphinin-4-one with chloral involves expansion of the six-membered heteroring to form 2-hydroxy-3-trichloromethyl-6,7-benzo-1,4,2λ5-dioxaphosphepin-5-one 2-oxide as a single diastereomer. The product was chlorinated with thionyl chloride to obtain (RS,SR)-2-chloro-3-trichloromethyl-6,7-benzo-1,4,2λ5-dioxaphosphepin-5-one 2-oxide.

Special features of reaction of 2-(5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-4H-benzo[d]-1,3,2-dioxaphosphorin-4-one with diethyl mesoxalate

Mixed anhydrides of salicylic and phosphoric (phosphonic) acids, salicylphosphites (phosphonites), are convenient and available reagents for the synthesis of derivatives of tetraand pentacoordinate phosphorus owing to the presence of the energy-rich Р–О bond [1]. Introducing to the atom of the tricoordinate phosphorus an additional diazaphosphol fragment containing a bicoordinate phosphorus could have both affected the regiochemistry of reactions of the salicylphosphites with activated carbonyl compounds and led to the formation of new reaction products. In this study by the reaction of previously described [2] 4-(dichlorophosphino)-5-methyl-2-phenyl-2H1,2,3-diaza phosphol with bis(О-trimethylsilyl) derivative of salicylic acid we prepared for the fi rst time 2-(5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)4H-benzo[d]-1,3,2-dioxaphosphorin-4-one (I) containing two phosphorus atoms of different coordination at a carbon atom (P=C–P) and investigated its reaction with diethyl mesoxalate. Common phosphorus derivatives of hydroxycarboxylic acids react with this compound forming phosphoranes and leaving intact the anhydride Р–О bond [3]; the introduction to the atom of the tricoordinate phosphorus of an isocyanate group leads to the formation of products of bicyclononane structure [4]. Although the molecule of compound I contains a reactive bicoordinate P atom, the reaction occurs exclusively at the tricoordinate P atom resulting in the formation of 2-(5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)2,5-dioxo-4,4-bis(diethyldicarbonyl)benzo[2,3-f]-1,3,2dioxaphosphepine (II). Thus 5-methyl-2-phenyl-2H1,2,3-diazaphosphol-4-yl substituent apparently owing to its electronic and steric effects directed the reaction to the path uncharacteristic of the diethyl mesoxalate involving

Reaction of 2-R-benzo[d]-1,3,2-oxazophosphorin-8-one with hexafluoroacetone. Synthesis and steric structure of 3-phenyl-9,9-bis(trifluoromethyl)-2-ethoxybenzo[d]-1,3,2-oxazaphosphepine-2,8-dione

Reaction of hexafluoroacetone with 2-R-benzo[d]-1,3,2-oxazophosphorin-8-ones leads to the formation of seven-membered nitrogen-containing heterocycles, the derivatives of 3-phenyl-9,9-bis (trifluoromethyl)benzo[d]-1,3,2-oxaza-phosphepine-2,8-diones. Steric structure of 2,3-diphenyl-9,9-bis (trifluoromethyl)-benzo[d]-1,3,2-oxazaphosphepine-2,8-di-one was established by X-ray structural analysis. By hydrolysis of the phosphepines a functionally substituted fluorinated ketone, 2-hydroxy-1-(2′-phenylamino)phenyl-2-trifluoromethyl-3,3,3-trifluoro)propan-1-one, was obtained.

Synthesis and Some Properties of 2-(5-Methyl-2-Phenyl-2H-1,2,3-Diazaphosphol-4-yl)-4H-Benzo[d]-1,3,2-Dioxaphosphorin-4-One

Abstract 2-(5-Methyl-2-phenyl-2Н-1,2,3-diazaphosphol-4-yl)-4H-benzo[d]-1,3,2-dioxaphosphorin-4-one 1 readily reacts with hexafluoroacetone, mesoxalic acid diethyl ester, trifluoropyruvic acid ethyl ester and chloral to give 2-(5-methyl-2-phenyl-2H-1,2,3-dizaphosphole-4-yl)-derivatives of 1,3,2- and 1,4,2-dioxaphosphepines. GRAPHICAL ABSTRACT

Cycloexpansion Reactions in Benzo[e]-1,3,2-diheterophosphorin-4-ones and 4-Oxo-1,3,2-dioxaphospholanes

Abstract The peculiarities of the reactions of 2-R-benzo[d]-1,3,2-dioxaphosphorin-4-ones, 2-R-naphtho[d]-1,3,2-dioxaphosphorin-4-ones, 2-R-8-azabenzo[e]-1,3,2-dioxaphosphorin-4-ones, and 2-R-1,3,2-dioxaphospholan-4-ones with unsaturated compounds are summarized in the review. The reactions proceed in the mild conditions and lead to the formation of the seven- and six-membered heterocycles 1,3,2-dioxa-, 1,3,2-oxaza-, 1,4,2-dioxa-, and 1,4,2-oxazaphosphepines and 1,3,2- and 1,4,2-dioxaphosphorinanes with a high regio- and stereoselectivity. The hydrolysis and thermolysis of the some benzophosphepine derivatives leads to the substituted fluorinated ketones and various nonphosphorus heterocycles.

Preparation and steric structure of 2-alkoxy-2,5-dioxo-4,4-bis(trifluoromethyl)-7(8)-chloro-1,3,2λ5-benzodioxaphosphepins. Effect of fluorinated fragments on the crystal packing

The reaction of hexafluoroacetone with 2-alkoxy-6(7)-chloro-1,3,2-benzodioxaphosphorin-4-ones yielded 7-and 8-chloro-substituted 2-alkoxy-2,5-dioxo-4,4-bis(trifluoromethyl)-1,3,2λ5-benzodioxaphosphepines. Their steric structure was studied by single-crystal X-ray diffraction. The effect of fluorinated substituents on the crystal packing of the benzophosphepines was demonstrated. Hydrolysis of these compounds gave the corresponding 4-and 5-chloro-substituted 2-(2-hydroxyphenyl)-2-oxo-1,1-bis(trifluoromethyl)-ethanols; the structure of 2-(2-hydroxy-5-chlorophenyl)-2-oxo-1,1-bis(trifluoromethyl)ethanol was also proved by single-crystal X-ray diffraction.

Tetracoordinate phosphorus cage compounds with endocyclic P–C bonds: Synthesis and reactivity

The survey summarizes modern methods of synthesis and reactivity of tetracoordinated phosphorus cage compounds containing one or more endocyclic P–C bonds (phosphine oxides, phosphinates and phosphonates, phosphatripticenes and others). Intramolecular cyclization reactions including electrophilic aromatic substitution with unsaturated organophosphorus compounds, reactions of P–H-derivatives with carbonyl compounds as well as cycloaddition reactions involving I–IV-coordinated phosphorus derivatives are considered.

Formation of cage phosphonate via hydrolysis of 2-(5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-1,5-dioxo-4-trifluoromethyl-4-ethoxycarbonylbenzo[f]-1,3,2-dioxaphosphepine

A new approach to obtaining of caged bicyclic phosphonate, 4-hydroxy-3-trifluoromethyl-3-ethoxycarbonyl-8-(1-phenylhydrazonoethyl)-5,6-benzo-2,7,1-dioxaphosphabicyclo[3.2.11.5]octane, based on hydrolysis of 2,5-dioxobenzo[f]1,3,2-dioxaphosphepine derivative bearing 5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl substituent at the phosphorus was developed. The hydrolysis process includes elimination of P(II) atom and intramolecular cyclization involving endocyclic carbonyl group of the phosphepine. Structure of the caged phosphonate was established by NMR and XRD methods.