Phosphorines

When immediately followed by -in or -ine, phospha- should be replaced by phosphor-, arsa- by arsen-, and stiba-by antimon-. The saturated six-membered rings corresponding to phosphorin and arsenin are named phosphorinane and arsenane. A further exception is the replacement of borin by borinane. 

Naphtho[2,1 -6]furan, 1,5,8-trimethyl- H NMR, 4, 562 (75JCS(P1)478) Naphtho[l,2-6]phosphorin, 2-t-butyl-5,6-dihydro-4-... 

Phosphorinanium iodide, 1-ethyl-l-phenyl-synthesis, 1, 500 Phosphorins, 1, 506-513 structure, 2, 7... 

Pyrylium salts such as 1704a and 3-azapyrylium salts 1704b react with P(SiMe3)3 1692 to give A -phosphorines 1706a [19] and 1706b [20], via 1705 (Scheme 11.4). 

A. Preparation.—The preparation of phosphorins from pyrilium salts and tris(hydroxymethyl)phosphine has been extended to include phosphorins with indolyl and pyrrolyl groups as substituents. ... 

B. Structure.—The crystal structure of l,l-bis(dimethylamino)-2,4,6-triphenylphosphorin shows that this compound is very similar in structure to the 1-alkyl- and 1-alkoxy-substituted phosphorins. ... 

Theoretical calculations of the electronic structure of phosphorin indicate that the Tr-charge-distribution is different to that of pyridine and cannot be explained by simple resonance theory. 

Substituted benzophosphabarrelenes (122) have been made from the reaction of phosphorins with benzyne. ... 

Substituted benzenes are obtained from the reaction of carbenes with phosphorins. The phosphepin (123) is thought to be an intermediate because the related compound (124) decomposes to a substituted benzene. 

Compound 39a reacts with N-methylbenzaldehyde imine as cycloaddend under the conditions metioned above — quite expectedly — to give a mixture of stereoisomeric 1 -oxa-3-aza-4Xs-phosphorins 37). 

The A5-phosphorin 164 and the bicyclic compound 165 are precursors of isopropyl metaphosphate, 16). Thermal fragmentation of 165 leads via [2 -I- 2]cycloreversion to triphenyltoluene 166 and isopropyl metaphosphate 167. The latter is identified as isopropyl phosphate after reaction with water. The mass spectrum of 165 is also dominated by this fragmentation picture (m/e 442 (16%) = M + m/e 320 (100%) = M + — 167). 

Phosphorin-3-carbonitrile, 4-amino-l-phenyl-1,2,5,6-tetrahydro-, 53, 99 Phosphorus heterocycles, 53,... 

Phosphorus. Substituted phosphorus analogues of pyridine (phosphinines, A3-phosphabenzenes, also called phosphonins or phosphorins) were first prepared by Markl starting from pyrylium cations their chemical properties suggest that their aromaticity is lower than that of pyridine (e.g. phosphinine 186, Scheme 72).230-232 Molecular calculations for other six-membered jr-systems with planar tricoordinate phosphorus, such as phospininines 186 and 187, have evidenced their aromaticity (Scheme 72).156... 

Property Unit Benzene Pyridine Phosphorin Arsenin Antimonin... 

Dimroth, K. Delocalized Phosphorus-Carbon Double Bonds. Phosphamethincyanines, X3-Phosphorins and 5-Phosphorins. 38, 1-150 (1973). 

The reaction of the stannane (176) with phosphorus trichloride gives the phosphorin (177). The electron-donating methyl group reinforces the ring dipole, the negative end of which is the phosphorus atom.189 The dibenzo analogue (178) has also been prepared and its electronic structure studied by photoelectron spectroscopy.160... 

The synthesis of the planar, tricyclic- A5-phosphorin (179) has been described.161 It reacts with methyl iodide to give the salt (180) as a mixture of stereoisomers, and is in equilibrium with the ylide (181), which reacts with benzaldehyde to give the oxide (182). 

A number of reactions of monocyclic phosphorins have also been described. The P-phosphorins (185) react with diazoalkanes in the presence of protic nucleophiles163 and with diazonium tetrafluoroborates in the presence of alcohols or phenols164 to give the P-phosphorins (186) and (187). 

P-Phosphorins having a phenyl residue at C-4 [e.g. (188)] are arylated in the aryl ring by aryldiazonium salts.165 The ethoxycarbonyl group of the A5-phosphorin (189) can be hydrolysed, transesterified, or reduced without destroying the ring system.166... 

The e.s.r. spectra of phosphorus compounds have been reviewed.101 The phosphorus hyperfine splitting (ap 33.5 G) of the radical anion (77) is within the 25—36 G range of phosphorin radical anions.102 The cis- and fra/w-isomers of 1,2-bisdiphenylphos-phinoethylene gave the same radical anion (78). The unpaired electron is coupled to all the protons in the molecule as well as to the two phosphorus atoms, and shows that the electron is completely delocalized. Only when caesium was used as the gegenion in THF could a metal interaction be detected. The spectrum in this case corresponded to the association of two caesium ions with the radical anion, the third... 

The aromaticity of pyridine and antiaromaticity of azete may be compared on the basis of the enthalpies of reactions (53) and (54). Both in structure (107) that corresponds to a minimum on the PES (unpublished results) and is an analog of the experimentally known X5-phosphorine (82ACR58) and in structure (108) a tetracoordinate nitrogen atom disturbs cyclic 7r-delocalization. In contrast to pyridine—Eq. (53)—the corresponding reaction for azete—Eq. (54)—is according to our AMI calculations exothermic. 

Another interesting rearrangement has been reported by Paddock and CO workers [171,172]. The reaction of sodium bis(trimethylsilyl)amide with A-methyl phosphazenium iodides N P Me2 +iI (n = 3, 4) gives the corresponding phosphorin derivatives (Eq. 30) via deprotonation and rearrangement. The crystal structure of the rearranged trimer derivative has been published [173]. 

---