Merck, 20025-25ML, 2-tert-Butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine

2-tert-Butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) is a phosphazene base. BEMP participates in the mild base catalyzed nucleophilic ring opening of N-sulfonyl aziridines. BEMP supported on polystyrene (PS-BEMP) has been reported as an efficient catalyst for the ring-opening of epoxides with phenols. BEMP is about 2000 times more basic and also much more sterically hindered than DBU (l,8-diazabicyclo[5.4.0]undecene).