Page 1. P. Jacob, W. Richter, I. Ugi 519 1,3,2h5-Benzothiazaphosphole 2-Oxide and 1,3,2h5-Benzoxazaphosphole 2-Oxide Derivatives, New and Versatile Phosphorylating Reagents Peter Jacob'), Wolfgang Richter and Ivar Ugi* ... Furthermore, Ramirez, Ugi et al.4) have ini- tiated the development of phosphorylating methods that ex- ploit the relatively high phoshorylation rates of five:mem- bered cyclic P(V) reagents5). ...