First organophosphorus radical-mediated cyclisations to afford medium-sized rings: Eight-membered lactones and seven- and eight-membered lactams

Article abstract of DOI:10.1016/j.tetlet.2005.04.032

The phosphorus based radical precursors N-ethylpiperidine hypophosphite (EPHP) and diethylphosphine oxide (DEPO) are efficient reagents for carrying out the formation of seven- and eight-membered rings. Esters and amides were successfully converted into the corresponding eight-membered lactones and seven- and eight-membered lactams in good to excellent yields.