ABSTRACT
A new class of annelated azaphospholes, namely 1,3-azaphospholo[1,5-f]phenanthridines, has been synthesized from the reaction of 5-(alkoxycarbonylmethyl/phenacyl)phenanthridinium bromides with phosphorus trichloride in the presence of triethylamine at room temperature. The reaction involves intramolecular 1,5-electrocyclization of the initially generated bis(phenanthridiniumylidyl)phosphenium chloride accompanied by 1,2-elimination to afford the title compounds in 15–64% yields. All the compounds so obtained are new and have been characterized by 31P-, 1H-, and 13C NMR studies. The C˭P functionality in these compounds is reactive and undergoes the Diels–Alder reaction with dimethylbutadiene with concomitant oxidation with sulfur at the phosphorus atom.
Acknowledgments
We thank the authorities of the IIS University, Jaipur (India) for providing facilities.
Funding
Financial support from the University Grants Commission, New Delhi is gratefully acknowledged.