Synthesis of Cyclophosphoramidates by Intramolecular C-H Amination

Significance Reported is a synthesis of six- and seven-membered cyclophosphoramidates by ­cobalt(II)-catalyzed intramolecular C-H amination effected by phosphoryl azides. A previously ­reported method for intramolecular amination of carbonyl azides catalyzed by commercially available [Co(TPP)] (TPP: tetraphenylporphyrin) (J. V. Ruppel, R. M. Kamble, X. P. Zhang Org. Lett. 2007 , 9 , 4889) was found to be ineffective for phosphoryl azide substrates. The success of [Co(II)(Por)] A may be the result of hydrogen-bond interaction between P=O and NH which activates the catalysis.