ISSN:
0947-6539
Keywords:
nitrogen heterocycles
;
phosphinocarbenes
;
ring expansions
;
ylides
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
[Bis(dicyclohexylamino)phosphino]trimethylsilylcarbene (1) reacts with benzonitrile leading to the corresponding 2-phosphino-2H-azirine 3 in 85% yield. Treatment of 3 with trifluoro-methanesulfonic acid, methyl trifluoro-methanesulfonate, or elemental sulfur leads to the P-hydrogeno-2-phosphonio-,P-methyl-2-phosphonio-, or 2-thioxo-phosphoranyl-2H-azirine (4, 5, and 7) in 77, 87, and 91% yields, respectively. Irradiation of 3 gives rise to the 1,2λ5-azaphosphete 8 (98% yield). Treatment of 3 with BF3·OEt2, BH3·SMe2, Lawesson's reagent, or methyl isothiocyanate gives heterocycles 9 (90% yield), 10 (76% yield), 12 (83% yield), or 13 (80% yield), while under the same experimental conditions, heterocycle 8 reacts with the same reagents to give 9 (82% yield), 11 (83% yield), 12 (86% yield), and 15 (56% yield), respectively. Thermolysis of the P-hydrogeno-2-phosphonio-2H-azirine 4 at 55°C leads to the cationic, four-membered heterocycle 17 (96% yield), while photolysis of the P-methylazirine analogue 5 in the presence of dimethyl acetylenedicarboxylate affords pyrrole 19 (64% yield). Irradiation of the thiox-ophosphoranyl azirine 7 gives the 1,3,5λ5-thiazaphosphole 20 in 79% yield. The influence of the coordination state of phosphorus on the reactivity of 2-phosphorus-substituted 2H-azirines is studied.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19970031106
