Reactivity and Synthetic Utility of 1,3,2λ5-Dioxaphospholanes

Abstract

The kinetics of Lewis acid-mediated decomposition and definitions of the synthetic applicability of 1,3,2λ⁵-dioxaphospholanes for (i) the syntheses of highly-hindered epoxides, and (ii) the stereospecific functionalizations of stereocenters in 1,2-diol arrays are described.     

Cyclic Elimination and Intramolecular Insertion Reactions of Thermally-Generated Monomeric Metaphosphoric Esters (Metaphosphates)

Abstract

2-Aryl-1,3,2-dioxaphospholanes (aryloxyphosphites) decompose thermally in the gas phase with loss of ethylene to generate aryl metaphosphates which cyclise by intramolecular insertion (phosphonylation) or abstract a β-hydrogen to form a terminal alkene by loss of HPO₃.     

Dialkyltriazaniumsalze, 1. Mitt.: Die Umsetzung von 2-Dialkylamino-1,3,2-dioxaphospholanen und 2-Dialkylamino-1,3,2-dioxaphosphorinan mit Chloramin in Gegenwart von Ammoniak

Zusammenfassung 2-Dialkylamino-1,3,2-dioxaphospholane und-phosphorinane reagieren mit Chloramin in Gegenwart von Ammoniak zu Dialkyltriazaniumchloriden und polymeren Phosphorverbindungen. Es ist dies bis jetzt die einzige Reaktion, bei der die Chloraminierung eines Dialkylaminophosphins nicht am Phosphor, sondern am Stickstoff stattfindet und Dialkyltriazaniumchloride in guter Ausbeute gebildet werden. Als erster Reaktionsschritt wird eine Spaltung der P-N-Bindung durch Chloramin angenommen. Die entstandenen Spaltprodukte, 2-Chlorphospholan und Dialkylhydrazin, reagieren mit Chloramin/Ammoniak weiter zu den gen. Endprodukten.

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2-Dialkylamino-1,3,2-dioxaphospholanes and-phosphorinanes react with chloroamine and ammonia yielding dialkyltriazanium chlorides and a polymeric phosphorus compound. This is the first chloroamination reaction where chloroamine reacting with a dialkyl aminophosphine apparently attacks the nitrogen and not the phosphorus atom yielding dialkylhydrazine and 2-chlorophospholane. These compounds then react with chloroamine and ammonia to give dialkyltriazanium chloride and a phosphorus compound of polymeric character.

     

α,β-Unsaturated Derivatives of Trivalent Phosphorus in Reactions with Activated Carbonyl Compounds

Abstract

Dialkyl alkynylphosphonites (I) react with esters and nitriles of α-oxocarboxylic acids to give phosphorylated alkanoates, 1,3,2-dioxaphospholanes and l-phosphabicyclohept-4-enes, depending on the nature of the reagent and conditions of the reaction. The reaction of dialkyl alkenylphosphonites (II) with esters and nitriles of α-oxocarboxylic acids predominantly leads to dioxaphospholane derivatives.     

Microstructure of poly(alkylene phosphates) related to biopolymers (teichoic acids)

The microstructure of polyphosphites and polyphosphates obtained by the ring-opening polymerization of asymmetrically substituted 5-membered cyclic phosphites was studied. It has been established, using ³¹P NMR, that 4-substituted 2-hydro-2-oxo-1,3,2-dioxaphospholanes underwent polymerization giving polymers with head-to-tail dyads as well as head-to-head and tail-to-tail structures. Analyses of ³¹P NMR spectra of racemic and optically active poly(2-hydro-4-methyl-2-oxo-1,3,2-dioxaphospholane) and model compounds estimated the statistical mode of ring scission of cyclic phosphites. Similar results were obtained for the polymerization of 4-acetoxymethyl-2-hydro-2-oxo-1,3,2-dioxaphospholane, which provided the simplest model of teichoic acid, namely poly(1,2-glycerol phosphate).     

Selective Functional Transformation of 1,2-Diols Via Organophosphorus Reagents

A new synthesis of 1,3,2λ⁵-dioxaphospholanes was realized by direct reaction of dibromotriphenylphosphorane with 1,2-diols. Ring opening studies were performed with or without electrophilic activation (Lewis acids or hydrogen bonding) in order to substitute selectively one of the hydroxy function.     

Oxaphosphoranylation of Methyl α-d-Glucopyranoside with Diethoxytriphenylphosphorane: Highly Stereoselective Approach to Anhydropyranosides

Diethoxytriphenylphosphorane (DTPP) efficiently oxaphosphoranylates methyl α-d -glucopyranoside to afford two unstable isomeric 1,3,2λ⁵-dioxaphospholanes. Thermolysis (60–90°C) of these 1,3,2λ⁵-dioxaphospholanes affords only two of four possible isomeric anhydropyranosides. Two distinct intermediate betaines and their unique “pre-transition state” chair or twist-boat structures are used to rationalize the regiochemistry-attending cyclodehydration. The decomposition of these rapidly interconverting 1,3,2λ⁵-dioxaphospholanes is accelerated in the presence of lithium bromide (LiBr) to afford a single anhydropyranoside.     

On the condensation of 2,2-difluoro-4-methyl-benzo[d]-1,3,2-dioxaborines with cyano acetic acid derivatives. Formation and transformation of 3-cyano-4-methyl-benzo[b]pyran-2-ones and their 2-imine precursors

Summary By condensation of 2,2-difluoro-4-methyl-benzo[d]-1,3,2-2H-dioxaborines (12) with cyano acetic acid derivatives in presence of weak bases, 3-cyano-4-methyl-benzo[b]pyran-2-ones (13) or their 3-cyano-4-methyl-benzo[b]pyran-2-imine precursors (14) are available in satisfactory yields.

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Zur Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen mit Cyanessigsäure- Derivaten. Bildung und Umwandlung von 3-Cyano-4-methyl-benzo[b]pyran-2-onen und ihrer 2-Imino-Vorstufen

Zusammenfassung Durch Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen (12) mit Cyanessigsäure-Derivaten in Gegenwart von Hilfsbasen entstehen in befriedigenden Ausbeuten 3-Cyan-4-methyl-benzo[b]pyran-2-one (13) oder ihre 3-Cyan-4-methyl-benzo[b]pyran-2-imino-Vorstufen (14).

     

Reaction of a 2H-1,2,3-Diazaphosphole with Ethane-1,2-Dithiol

Abstract

Reaction of 2-acetyl-5-methyl-2H-1,2,3-diazaphosphole with ethane-1,2-dithiol at ?30°C leads to the formation of 2-acetyl-3-(β-mercaptoethylthio)-5-methyl-1,2,3-diaza-phospholene. On heating, this product forms 2-(β-mercaptoethylthio)-1,3,2-dithia-phospholane, 1,2-bis(1,3,2-dithiaphospholanyl)-dithioethane, and N-acetyl-N′-isopropilidene-hydrazine.     

Allene-Substituted-1,3,2-Dioxaphospholanes in the Reactions with Sulfenyl Bromides and Selenenyl Bromides

The reactivity of allene-substituted-1,3,2-dioxaphospholanes towards sulfenyl bromides and selenenyl bromides has been investigated, and 2,5-dihydro-1,2-oxaphosphole derivatives have been obtained.     

1,2-2(H)-1,3,2-Benzoxazaphosphorine-2-Sulfide

Abstract

Reports [1-5] concerning the preparation of benzo-1,3,2-benzoxazaphosphonaline containing a substituent on nitrogen have been published. The synthesis of parent compund, 1,2-dinydro-1,3,2-benzoxazaphosphorine, has not been reported. We found that it can be easily synthesized pY the reaction of salicylic aldehyde with O-alkyl-phosphoryl dichlorides and ammonia.     

ORGANISCHE PHOTOCHEMIE XXIX1,2 Synthese und Photoreaktionen eines Aroyl-Diphenylphosphins‐Eine neuartige Photoinduzierte Sauerstoff-Transferreaktion

Abstract

Es wird die Synthese und Photolyse des neuen [2-Brom-α-oxo-phenylmethan]-diphenylphosphins (5) beschrieben. UV-Bestrahlung von (5) in Benzol liefert Produkte durch x-Spaltungen (6 und 7) und Photosubstitutionen (7 und 8) sowie das Phosphinoxid (9) durch neuartige Umlagerungsreaktion. Die Bildung von (9) wird durch photoinduzierten 1,2-Sauerstofftransfer aus der Carbonylgruppe auf den Phosphor erklärt. Von (9) wird eine Röntgenstrukturanalyse vorgelegt.

Synthesis and photolysis of the new [2-bromo-α-oxo-phenylmethane]-diphenylphosphine (5) is described. U. v. irradiation of (5) in benzene yields products via α-cleavages (6 and 7), and photosubstitutions (7 and 8), and the phosphine oxide (9) in a novel rearrangement reaction. The formation of (9) is interpreted by photoinduced 1,2-transfer of oxygen from the carbonyl function onto the phosphorous atom. An X-ray structure analysis of (9) is presented.     

Interaction of Cyclohexanediimines with Phosphorus (III) Chlorides

Abstract

It is known that reactions of phosphorohalidites with linear a-diimines proceed accordingly [1+4]-cycloaddition mechanism and give rise to 1,3,2-diazaphosphol-r-enes. We have found that 1,2-cyclohexane-diirnines (1) react with alkyldichlorophosphines in the absence of base also resulting in the formation of products of 1,3,2-diazaphosphol-4-ene structure (2,3).     

DARSTELLUNG UND NMR-SPEKTROSKOPISCHE UNTERSUCHUNGEN DER 2-FLUOR-2,2-DIPHENYL-2,3-DIHYDRO-1,3,2λ5-BENZOXAZAPHOSPHOLE

Abstract

Pentakoordinierte Phosphorverbindungen vom Typ der 2.3-Dihydro-1.3.2-benzoxazaphosphole entstehen bei der Umsetzung von 2-Amino-phenolen oder N-Äthyl-2-hydroxy-anilinen mit Diphenyl-trifluorphosphoran unter Verwendung von Triäthylamin als Fluorwasserstoff-Akzeptor. Die Synthese einer großen Anzahl verschieden substituierter Spezies zeigt die Allgemeingültigkeit dieses Verfahrens. Die isolierbaren Substanzen werden durch NMR-Spektren (¹H, ³¹P, ¹⁹F) und die üblichen analytischen Methoden charakterisiert. Die Markierung einer Verbindung mit ¹⁵N trägt wesentlich zur Struktursicherung bei. Bei den 3-H-2-Fluor-2.2-diphenyl-1.3.2-benzoxazaphospholen wurde ein bemerkenswerter Zusammenhang zwischen P–F-Kopplungskonstante und dem F-shift aufgefunden, der eine lineare Korrelation dieser beiden Größen erkennen läßt.

Pentacoordinated phosphorus compounds of the type of 2,3-dihydro-1,3,2-benzoxazaphospholes originate from reaction of 2-aminophenol or N-ethyl-2-hydroxyaniline with diphenyl-trifluorophosphorane using triethylamine as an HF-acceptor. The described synthesis of a great number of differently substituted species indicates the wide field of application. The substances are characterized by nmr spectroscopy (¹H, ³¹P, ¹⁹F) and the usual analytical methods. By marking one compound with ¹⁵N the structure assignment is proved. Remarkably, the compounds of the type 3-H-2-fluoro-2,2-diphenyl-1,3,2-benzoxazaphospholes exhibit a nearly linear correlation between the P–F-coupling constants and the F-chemical shift.     

Synthesis and Isomer Composition of 2-Polyfluoroalkoxy-1,3,2-dioxaphospholanes and -phosphinanes

Polyfluoroalkanols readily reacted with 2-chloro-1,3,2-dioxaphospholanes and 2-chloro-1,3,2-dioxaphosphinanes in hexane in the presence of triethylamine (–10 to 25°C, 5 h) to give 2-polyfluoroalkoxy-1,3,2- dioxaphospholanes and 2-polyfluoroalkoxy-1,3,2-dioxaphosphinanes in 48–72% yield. The products were found to exist as mixtures of cis and trans isomers with the trans isomer predominating for the phospholanes and cis isomer predominating for the phosphinanes according to the ¹H, ¹³C, ¹⁹F, and ³¹P NMR data.     

λ3σ3P and λ5σ5P derivatives of (E)-1,2-difluoro-2-(pentafluoro-λ6-sulfanyl)ethylene and (Z)-1,2,3,3,3-pentafluoropropylene

For the first time, the (E)-1,2-difluoro-2-(pentafluoro-λ⁶-sulfanyl)ethenyl group has been bonded to λ³σ³ phosphorus using a Grignard reagent. Similar phosphorus derivatives containing the (Z)-1,2,3,3,3-pentafluoropropenyl moiety were also synthesized for comparison. In three cases, hexafluoroacetone was added to form 4,4,5,5-tetrakis(trifluoromethyl) 1,3,2λ⁵σ⁵-dioxaphospholanes. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 467–471, 1997     

Regioselective Substitutions of Unsymmetrical 1,2-Diols using Dioxaphospholanes: Applications to Carbohydrates

Abstract

For several years, the method employing 1,3,2λ⁵dioxaphospholanes to effect regioselective substitution of unsymmetrical 1,2-diols has been investigated.^[1] As carbohydrates are an abundant source of diols, this study has been extended to the use of 1,2-O-isopropylidene- D-ghCOfuranOSe 1. We have synthesized a single dioxaphospholane 2 and subsequently treated it with trimethylsilyltriflate to form oxyphosphonium ions 3 and 4.     

P,P,P-Trihalobenzo-1,3,2-Dioxaphopholes in the Reaction with Aliphatic Acetylenes and Diacetylenes: Synthesis of New Phosphacoumarins

Abstract

Bis(benzo[e]-1,2-oxaphosphinin-2-oxid-4(7)-yl)butane (-benzene) derivatives were synthesized for the first time both on the basis of reactions of diacetylene with P,P, P-trihalobenzo-1,3,2-dioxaphopholes and on the basis of reactions of bis(P,P,P-trihalobenzo-1,3,2-dioxaphosphol-5-yl)bytane (-benzene) with phenylacetylene.     

Jacobsen-type enantioselective hydrolysis of aryl glycidyl ethers. 31P NMR analysis of the enantiomeric composition of oxiranes

The enantioselective partial hydrolysis of a number of racemic aryl glycidyl ethers in the presence of chiral Co(salen)-catalyst was studied. The enantiomeric composition of the isolated (R)-aryl glycidyl ethers was analyzed by ³¹P NMR using optically active substituted 2-chloro-1,3,2-dioxaphospholanes. A synthesis of -adrenoblocking agents (S)-toliprolol and (S)-moprolol based on the simultaneously obtained (S)-3-aryloxypropane-1,2-diols was proposed.     

Synthesen mit Nitrilen, 23. Mitt.

Zusammenfassung Die Bedingungen für die Kondensation von Benzil mit monomerem und dimerem Malonsäurenitril werden überprüft und für das 2-Benzoyl-2-phenyl-äthylen-1,1-dicarbonitril (2a) sowie das 2-Amino-4-benzoyl-4-phenyl-1,3-butadien-1,1,3-tricarbonitril (1a) die Strukturen sichergestellt. Unter dem Einfluß von wäßrigen Alkalien erleidet2a eine 1,2-Arylverschiebung und durch Cyclisierung entsteht das 2,5-Dioxo-4,4-diphenyl-pyrrolidin-3-carbonitril (7a).

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Syntheses with nitriles, XXIII.: Anionotropic 1,2-Shift of aryl groups in benzil-malononitrile condensation products

The condensation conditions of benzil with monomeric and dimeric malononitrile have been reinvestigated and the structures of 2-benzoyl-2-phenyl-ethylene-1.1-dicarbonitrile (2a) and 2-amino-4-benzoyl-4-phenyl-1.3-butadiene-1.1.3-tricarbonitrile (1a) elucidated. With aqueous alkali2 undergoes 1.2-arylmigration and cyclization yielding 2.5 dioxo-4.4-diphenyl-pyrrolidine-3-carbonitrile (7a).