- Phosphole
Phosphole is the
organic compound with thechemical formula C4H4PH; it is thephosphorus analog ofpyrrole . The term phosphole also refers to substituted derivatives of the parentheterocycle . These compounds are of theoretical interest but also serve asligand s for transition metals and as precursors to more complexorganophosphorus compound s.The first phosphole was discovered in 1953, pentaphenylphosphole followed in 1959 and the parent compound, phosphole itself, was first synthesized in 1987 ["A Guide to Organophosphorus Chemistry" Louis D. Quin 2000 John Wiley & Sons ISBN 0-471-31824-8] . Phenylphospholes can be prepared via treatment of an organozirconium compound with PhPCl2. [OrgSynth | author = Paul J. Fagan and William A. Nugent | title = 1-Phenyl-2,3,4,5-Tetramethylphosphole| collvol = 9 | collvolpages = 653| year = 1998 | prep = CV9P0653]
Unlike other the 5-membered heterocycles pyrrole,
thiophene , andfuran , thearomatic ity of phospholes is diminished, reflecting the reluctance of phosphorus to delocalize itslone pair . [D. B. Chesnut, L. D. Quin "The important role of the phosphorus lone pair in phosphole aromaticity" Heteroatom Chemistry 2007, Volume 18754-758. DOI: 10.1002/hc.20364.] For example, phospholes undergoDiels-Alder reaction s withelectrophilic alkyne s. :See also
*
Organophosphorus chemistry
*Phosphorine References
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