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Formation of 2,3‐dihydro‐1,3,2‐benzoxazaphospholes by cheletropic reaction of o ‐quinone monoimines with triphenylphosphane. Crystal and molecular structures of 2,3‐dihydro‐2,2,2‐triphenylphenanthro[9,10‐ d ]‐1,3,2λ 5 ‐oxazaphosphole and 5,7‐di‐ tert ‐butyl‐2,3‐dihydro‐2,2,2‐triphenyl‐1,3,2λ 5 ‐benzoxazaphosphole
Author(s) -
Speier Gábor,
Tyeklár Zoltán,
Fülöp Vilmos,
Párkányi László
Publication year - 1988
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19881210923
Subject(s) - chemistry , tautomer , quinone , crystal structure , cycloaddition , benzoquinone , stereochemistry , x ray crystallography , medicinal chemistry , molecule , crystallography , diffraction , organic chemistry , catalysis , physics , optics
9,10‐Phenanthrenequinone monoimine ( 1c ) or 3,5‐di‐ tert ‐butyl‐ o ‐benzoquinone ( 2a ) in the presence of ammonia undergo cycloaddition with triphenylphosphane to give 2,3‐dihydro‐1,3,2λ 5 ‐benzoxazaphospholes ( 3 ) in good yields. 5,7‐Di‐ tert ‐butyl‐2,3‐dihydro‐2,2,2‐triphenyl‐1,3,2λ 5 ‐benzoxazaphosphole ( 3a ) shows a tautomeric equilibrium with the iminophosphorane 4a while 2,3‐dihydro‐2,2,2‐triphenylphenanthro[9,10‐ d ]‐1,3,2λ 5 ‐oxazaphosphole ( 3c ) has a cyclic structure in solution. Both compounds are cyclic in the solid form as confirmed by X‐ray structure diffraction studies.