Carbon-phosphorus heterocyclics

K. D. Berlin u. D. M. Hellwege, Carbon-Phosphorus Heterocycles, Topics in Phosphorus Chemistry 6, 1 (1969). H. Schmidbaur, Isoelectronic Species in Organophosphorus, Organosilicon and Organoaluminium Series, Advances in Organometallic Chemistry 9, 260 (1970). 

K. D. Berlin u. D. M. Hellwege, Carbon-Phosphorus Heterocycles, Topics in Phosphorus Chemistry 6, 83 (1969). 

The initial impetus for the research in this field came from the observation that it was impossible to directly functionalize by electrophilic attack (or by any other means) any theoretically aromatic carbon-phosphorus heterocycle, thus precluding the development of an interesting new chemistry. For exemple, up to now, no electrophilic attack at carbon was recorded for fi ee phospholyl anions or for phosphorins XLFV. Such is not the case with arsenic, as Ashe ... 

Berlin, K.D., and Hellwege, D.M., Carbon-phosphorus heterocycles, in Topics in Phosphorus Chemistry, Vol. 6, John Wiley Sons, New York, 1969, pp. 1-186. 

S.D. Venkataramu et al.. Polycyclic carbon-phosphorus heterocycles, Chem. Revs., 77, 121, 1977. 

K.D. Berlin and D.M. HeUwege, Carbon-phosphorus heterocycles. Topics Phos. Chem., 6, 1, 1969. 

Polycyclic carbon-phosphorus heterocycles have been reviewed. 

Redmore, D., Phosphorus derivatives of nitrogen heterocycles. 3. Carbon-phosphorus bonding in pyridyl-2- and -4-phosphonates, /. Org. Chem., 38, 1306, 1973. 

Fig. 5.9. 13Cf1 - NMR spectrum of flavin adenine dinucleotide (FAD), disodium salt, 30 mg in 1 ml, of deuterium oxide 30 °C 100.576/400.133 MHz (13C/ H) 5000 interferograms (32K/15000 Hz) (a) sp3 carbon partial spectrum (20-92 ppm) with expanded output (b) to display carbon-phosphorus couplings (2JCI, for A5 and R5 3Jcr for A4 and R4 carbon nuclei) (c) partial spectrum of heterocyclic carbon nuclei (117-167 ppm). Signals are assigned according to ref. [147].

A short time ago numerous triorganyl-cyclotriphosphanes have become accessible as pure substances on various synthetic routes (2). Moreover, three-membered phosphorus heterocycles with carbon, silicon, germanium, arsenic, boron, and sulfur as hetero ring atoms could be synthesized (2). Recently, we have found that such compounds with elements of the fifth periodtare als stable enough fop existence. Through the reaction of K(Bu )P-P(Bu )K with Bu S C1 or Bu -SnC at -78°C, the diphosphastib rane ... 

Rearrangement processes of alkyltitanocene dichlorides that occur under electron impact have been investigated using deuterium labelling. A novel type of zirconium-mediated coupling reaction of alkynes with vinyl bromide to afford 2,3-disubstituted dienes has been reported (see Scheme 105), and an inter-intramolecular reaction sequence has been proposed for the observed formation of vinylcyclohexadienes and/or methylenecycloheptadienes from the copper-catalysed reaction of zirconacyclo-pentadienes with allylic dichlorides. The essential step in these processes appears to be transmetallation of the zirconium-carbon bond of the zirconacyclopentadiene to produce a more reactive copper-carbon bond. New phosphorus heterocycles, e.g. (417), have been constructed by the thermal rearrangement of a [l,4-bis(trimethylsilyl)->/ -cyclooctatetraene]- ,3,5-triphospha-7-hafhanorbomadiene complex (416). 

A series of four-membered Si- or P-containing heterocycles was produced in various yields by electrocyclization or [2-t-2]-dimerization of compounds with multiple carbon-silicon or carbon-phosphorus bonds. These unsaturated species are formed under photolysis of diazo compounds containing a P or Si atom in an a position with respect to the diazo group, following a [l,2]-sigmatropic shift in the intermediate carbene. 

In contrast to their aU-carbon analogues, phosphaalkyne cyclooligomers only became accessible a few years ago. A milestone in the chemistry of the cyclotrimers was the synthesis and structm-al characterization of the 1,3,5-triphosphinines 11, obtained by the trimerization of phosphaalkynes in the presence of a vanadimn catalyst. This review is focused on the reactivity of these new phosphorus heterocycles. 

A single crystal X-ray structure determination of 2,4,6-tri-tert-butyl-1,3,5-triphosphinine (11a) also provided indications for the aromatic nature of these heterocyclic compounds. The analysis shows a planar, hexagonal basic skeleton with average carbon-phosphorus bond lengths of 1.727 A, a value lying between those for carbon-phosphorus single and double bonds [14,23]. 

Ti -Cyclopentadienyl(triphenylphosphine)cobalt reacts with phosphites and forms complexes of 1-alkoxyphosphole oxides 251 (R = Me, Et, Ph) through a step involving (ri -cyclopentadienyl)(phosphite)cobalt (80JA4363). (ri -Cp)Co(PF3)2 reacts with hexafluorobut-2-yne and 252 is formed, which hydrolyzes into 253 (X = OH) [73JCS(CC)583 75JCS(D)197]. The five-member ring has the envelope conformation, in which the carbon atoms are coplanar, and the phosphorus atom deviates from this plane in the direction opposite to the cobalt atom. The heterocycle is a four-electron donor relative to the metal center. 

As well as phosphorus ligands, heterocyclic carbenes ligands 10 have proven to be interesting donor ligands for stabilization of transition metal complexes (especially palladium) in ionic liquids. The imidazolium cation is usually presumed to be a simple inert component of the solvent system. However, the proton on the carbon atom at position 2 in the imidazolium is acidic and this carbon atom can be depro-tonated by, for example, basic ligands of the metal complex, to form carbenes (Scheme 5.3-2). 

MatheyF (ed) (2001) Phosphorus-carbon heterocyclic chemistry the rise ofa new domain. Elsevier... 

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