Selective Phosphoramidation and Phosphonation of Benzoxazoles via Sequence Control.

A selective phosphoramidation and phosphonation of benzoxazole was developed with trialkyl phosphites in the presence of iodine under mild conditions. In the reaction, the transformation completes in 10 min at room temperature and the substrates are well tolerant, as 2-substituted azoles could afford the quaternary carbon-centered products. Significantly, phosphites could be selectively introduced into the C- and N-positions of the benzoxazoles by controlling the addition sequence and the ratio of substrates.