ORGANOPHOSPHORUS COMPOUNDS .48. 1-HALOGEN-1H-PHOSPHIRENES FROM PHOSPHAALKYNES AND CHLOROCARBENES

Halogen-substituted carbenes (7a-i), generated by thermolysis of diazirines (11a-i), add onto phosphaalkynes (8a-c) to form the title compounds (10a-1). Initially formed 2H-phosphirenes (9) could not be detected as their subsequent conversion to the 1H-isomers 10 by a 1,3-halogen shift is very fast. Hydrolysis of 10c,e,g-i and k yields vinylphosphonous acids (17a-e). 1-Chloro-1H-phosphirenes are transformed by nucleophilic substitution into fluoro (10a,c,e --> 19a-c), bromo (10c,e --> 20a,b), and iodo analogs (10c,e --> 21a,b) with the help of silver tetrafluroborate, trimethylsilyl bromide, and trimethylsilyl iodide, respectively. A crystal structure analysis of 10 c is reported.