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     

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.     

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.     

Diastereospecific synthesis of β-heterosubstituted alcohols from 1,2-diols via 1,3,2λ5-dioxaphospholanes

The stereochemistry of the ring opening of (R,S) or (R,R)-4,5-dimethyl-2,2,2-triphenyl-1,3,2λ⁵-dioxaphospholanes (prepared by reaction of (R,S) or (R,R)-butane-2,3-diol with dibromotriphenylphosphorane) by aniline or thiophenol was investigated. The reaction affords stereoselectively the corresponding β-anilino- or β-phenylthioalcohols with a nearly complete inversion of stereochemistry at the stereogenic reaction centre.     

Umsetzung von 2-Azidoalkoholen mit Trialkylphosphiten Bildung von Aziridinen und Amidophosphorsäureesten via Imidophosphorsäureester und 1,3,2λ5-Oxazaphospholidine

Reaction of 2-Azidoalcohols with Trialkylphosphites. Formation of Aziridines and Amidophosphates via Imidophosphates and 1,3,2λ⁵-Oxazaphospholidines The 2-azidoalcohols 1 and 2 react with trialkyl phosphites to trialkyl (2-hydroxy-alkyl)imidophosphates 10, 14 , and 15 respectively, whereas the 2-azidoalcohols 3-7 yield the 2,2,2-trialkoxy-1,3,2λ⁵-oxazaphospholidines 16–22 under the same reaction conditions (Scheme 2). The dialkyl (2-hydroxyalkyl)amidophosphates 23, 25 , and 27–34 are obtained by the reaction of 10 , and 14–22 with water (Scheme 3 and 4). By reaction with alcohols, however, both the imidophosphates 10, 14 and 15 and the 1,3,2λ⁵-oxazaphospholidines 16–22 are transformed to aziridines 24, 26 , and 35–38 (Scheme 5). The reactions of the imidophosphates seem to proceed via 1,3,2λ⁵-oxazaphospholidines.     

Reactions of Arylenedioxytrihalophosphoranes with Acetylenes: XV.<Superscript>1</Superscript> Reaction of 2,2,2-Tribromo-4,6-di-<Emphasis Type="Italic">tert</Emphasis>-butylbenzo-1,3,2λ<Superscript>5</Superscript>-dioxaphospholedioxaphosphole with Pent-1-yne

2,2,2-Tribromo-4,6-di-tert-butylbenzo-1,3,2λ⁵-dioxaphospholedioxaphosphole reacted with a terminal alkyne, pent-1-yne, to give a mixture of two isomeric 1,2-benzoxaphosphinine derivatives, 6,8- and 5,7-di-tert-butyl-2-bromo-4-propylbenzo-1,2λ⁵-oxaphosphinin-2-oxides, at a ratio of 5.9: 1. The regioselectivity of substitution of oxygen in the dioxaphosphole fragment by carbon differs from that observed previously in the reaction with 4,6-di-tert-butyl-2,2,2-trichlorobenzo-1,3,2λ⁵-dioxaphosphole: the minor isomer was formed as a result of substitution of the oxygen atom in the ortho position with respect to one tert-butyl group of the initial phosphole.     

2,4-Bis(4-methylpheylthio)-1,3,2λ5,4λ5-dithiadiphosphetan-2,4-dithion: Ein neues Reagens zur Schwefelung von N,N-disubstituierten Amiden

2,4-Bis(4-methylphenylthio)-1,3,2λ⁵,4λ⁵-dithiadiphosphetane-2,4-dithione: A New Reagent for Thiation of N,N-Disubstituted Amides As a new reagent for the thiation of amides, the easily accessible 2,4-bis(4-methylphenylthio)-1,3,2λ⁵,4λ⁵-dithiadiphosphetane-2,4-dithione ( 9 ) shows a remarkable selectivity. This selectivity – the preferred thiation of N,N-disubstituted amides – is complementary to the one of the well known Lawesson reagent. Thiation of diamides of type 2 with 9 leads via cyclization of the corresponding dithiodiamides to 1,3-thiazole-5(4H)-thiones 1 (Scheme 3).     

Benzooxaza- und Benzodiaza-λ3-phosphole und deren Reaktion zu spirocyclischen λ5-Phospholen

Benzooxaza- and Benzodiaza-λ³-Phospholes and their Conversion to Spirocyclic λ⁵-Phospholes 2,3-Dimethyl-1,3,2λ³-benzooxazaphosphole and 1,2,3-trimethyl-1,3,2λ³-benzodiazaphosphole are obtained by transamination of methylbis(dimethylamino)phosphane with N-methyl-o-aminophenol and N,N′-dimethylamino-o-phenylenediamine. These compounds are converted by oxidation and disproportionation reactions to spirocyclic λ⁵-phospholes. The crystal structure of 2-methyl-2,2′-spirobi(1,3-dimethyl-1,3,2λ⁵-benzodiazaphosphole) is established and a trigonal bipyramidal geometry of the molecule has been found.     

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.     

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).     

Conformational analysis: XIV—A 1H n.m.r. conformational study of methyl substituted 2-oxo-1,3,2-dioxathians to confirm the predominance of chair forms in the trimethylene sulphite series

Seven isomeric 4,5,6-trimethyl-2-oxo-1,3,2-dioxathians, cis-4-trans-6-dimethyl-r-2-oxo-1,3,2-dioxathian and two isomeric 4,5,5,6-tetramethyl-2-oxo-1,3,2-dioxathians were prepared and their ¹H n.m.r. spectra analysed. The values of the vicinal coupling constants reported earlier for the cis-4-trans-6 compound were shown to be erroneous. In all cases the values of the vicinal coupling constants (and those of the chemical shifts) are indicative of a single chair conformation or a chair-chair equilibrium, in contrast to earlier reports on the significant contribution of twist forms but in agreement with an electron diffraction study. The chair form is ? 31 kJ mol^?1 thermochemically more stable than the twist form.     

Reaction of tartaric acids with triethyl phosphite

Conclusions The formation of the isomeric 2-ethoxy-4,5-di(carbethoxy)-1,3,2-dioxaphospholanes occurs when triethyl phosphite is transesterified with the D-, DL-, and mesotartaric acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 653–655, March, 1973.     

An NMR study of 2-alkoxy-1,3,2-dioxaphospholanes. I—13C chemical shifts

Measurements of the ¹³C chemical shifts of 2-alkoxy-1,3,2-dioxaphospholanes have allowed the determination of the contribution of the substituent to the α-, β- and γ-carbon chemical shifts of attached alkyl groups. The preliminary assignments of the signals were made using the following information; relative intensities, variations in coupling constants J(³¹P¹³C) and the existence of linear correlations between the shifts of carbon atoms in the P-alkoxy groups and the degree of substitution of the observed carbon or of its neighbours.     

1H-, 31P- and 13C-NMR spectra of some 2-arylsulphonylamido-2-thiono-5-methyl-1,3,2-dioxaphospholanes

Some 2-arylsulphonylamido-2-thiono-5-methyl-1,3,2-dioxaphospholanes (1), containing two chiral centres, give NMR spectra in which splittings of the ¹H and ¹³C signals of the 5-methyl substituent and of the ³¹P signal indicate that they exist in an approximately 70:30% ratio of two racemic mixtures, Z and E respectively, diastereomeric to each other. These splittings were invariably observed for compounds 1a, containing a monosubstituted sulphonylamido group (Y = H) and various substituents at position 4′ of the aryl group, X = H, CH₃, OCH₃, F, CI and Br. The methylenic protons in position 4 of the phospholane ring are diastereotopic and therefore magnetically non-equivalent. Benzene-induced shifts were measured for the Z isomers of compounds 1a, X = H, F and for compound 1b, containing an N-disubstituted sulphonylamido group (Y = CH₃) and X = H; the tentative interpretation of these shifts places the more shielded diastereotopic methylene proton on the same side of the ring as the 5-methyl substituent. The H? P and H? H coupling constants indicate that the preferred conformation of the dioxaphospholane ring should be a ‘twisted envelopey’ shape with the 5-methyl substituent in the equatorial position.     

ZUR REAKTION VON ORGANODICHLORPHOSPHINEN MIT 1,2-DIOLEN

Abstract

Die Reaktion von Organodichlorphosphinen mit aliphatischen 1,2-Diolen in Abhängigkeit von der Basenkonzentration und den Substituenten wird untersucht; das Produktspektrum umfaßt neben 1,3,2-Dioxaphospholanen auch 2-Oxo-1,3,2-dioxaphospholane und Oxiphosphorane. Letztere lassen sich zum Hauptprodukt machen.

The reaction of phosphorus dichlorides with aliphatic 1,2-diols is studied. The range of products varies strongly with the concentration of the base and the organic substituents. In addition to 1,3,2-dioxaphospholanes the corresponding 2-oxo-1,3,2-dioxaphospholanes and oxiphosphoranes are also formed. Using proper conditions the latter may become the dominant product.     

Synthese,Struktur, Elektrochemie und optische Eigenschaften von alkinylfunktionalisierten 1,3,2‐Diazaborolen und 1,3,2‐Diazaborolidinen

Syntheses, Structures, Electrochemistry and Optical Properties of Alkyne‐Functionalized 1,3,2‐Diazaboroles and 1,3,2‐Diazaborolidenes The reaction of 2‐bromo‐1,3‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborole ( 3 ) with lithiated tert‐butyl‐acetylene and lithiated phenylacetylene affords the 2‐alkynyl‐functionalized 1,3,2‐diazaboroles 4 and 5 as a thermolabile colorless oil ( 4 ) or a solid ( 5 ). Similarly 2‐bromo‐1,3‐diethyl‐2,3‐dihydro‐1H‐1,3,2‐benzodiazaborole ( 6 ) was converted into the crystalline 2‐alkynyl‐benzo‐1,3,2‐diazaboroles 7 and 8 by treatment with LiC≡C–tBu or LiC≡CPh, respectively. 2‐Ethynyl‐1,3‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborole ( 2 ) was metalated with tert‐butyl‐lithium and subsequently coupled with 2‐bromo‐1,3,‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborole ( 3 ) to afford bis(1,3‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborol‐2‐yl)acetylene ( 9 ) as thermolabile colorless crystals. Analogously coupling of the lithiated species with 6 or with 2‐bromo‐1,3‐ditert‐butyl‐1,3,2‐diazaborolidine ( 11 ) gave the unsymmetrically substituted acetylenes 10 or 12 , respectively, as colorless solids. Compounds 4 , 5 , 7 – 10 and 12 are characterized by elemental analyses and spectroscopy (IR, ¹H‐, ¹¹B{¹H}, ¹³C{¹H}‐NMR, MS). The molecular structures of 5 , 8 and 9 were elucidated by X‐ray diffraction analyses.     

Synthesis of dimeric 1,3,2λ5-benzoxazaphospholes from phosphinic acid derivatives by silylation/desiloxylation

The reaction of N,N,O-tris(trimethylsilyl)-o-aminophenol with two equivalents of phosphinic chloride yielded dimeric 2,2-disubstituted 1,3,2λ⁵-benzoxazaphospholes and trimethylsilyl phosphinate. The chlorides having the bulk substituents (o-chlorophenyl or tert-butyl) at phosphorus or containing P N and P O bonds (instead of a P C bond) either didn't react at all or reacted to retain the phosphoryl group. Being stable in solution at 20°C, the individual diastereoisomers of dimeric 1,3,2-benzoxazaphospholes were converted upon warming to an equilibrium mixture of isomers. When reacted with another dimer each gave a mixed dimeric compound having two different phosphorus atoms in the molecule.     

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.     

Reaction of trihalo(phenylenedioxy)phosphoranes with acetylenes: X. specific features of the reactions of substituted 2,2,2-trichloro-1,3,2λ5-benzodioxaphospholes with 3-chloro(bromo, iodo)propynes

It was shown for the first time that 3-chloro-, 3-bromo-, and 3-iodopropynes can react with 2,2,2-trichloro-, 2,2,2-trichloro-5-methyl-, and 5,6-dibromo-2,2,2-trichloro-1,3,2λ⁵-benzodioxaphospholes to give derivatives of 4-(halomethyl)-2-chloro-2H-1,2λ⁵-benzoxaphosphinin-2-ones. The reaction involves nonselective chlorination of the phenylene substituent in different positions, and the resulting isomer ratio is temperature-dependent. In the reactions of 3-bromo-and 3-iodopropynes with 2,2,2-trichloro-1,3,2λ⁵-benzo-dioxaphosphole, a side process takes place, viz. nucleophilic substitution of bromine and iodine with chlorine. The structure of some of the prepared 4-(chloromethyl)-1,2-benzoxaphosphinines was studied by means of X-ray diffraction.     

Synthesis and steric structure of 3,4-dimethyl-2-(3-methyl-1-phenylbuta-1,2-dienyl)-5-phenyl-1,3,2λ<Superscript>5</Superscript>-oxazaphospholane 2-oxide

Allenic 1,3,2-oxazaphospholanes on the basis of d-pseudoephedrine were synthesized. The steric structure of 3,4-dimethyl-2-(3-methyl-1-phenylbuta-1,2-dienyl)-5-phenyl-1,3,2λ⁵-oxazaphospholane 2-oxide was determined by X-ray diffraction.