Epoxides 4-dimethylaminopyridine

From Srivatsava et al (248). Reaction conditions catalyst (TS-1 Si/Ti = 36, Ti-MCM-41 Si/Ti = 46), 100 mg co-catalyst, 0.0072 mmol epoxide, 18 mmol CH2CI2, 20 mL CO2, 6.9 bar. DMAP N,N-dimethylaminopyridine EC epichlorohydrin PO propylene oxide SO stytene oxide BO a-butylene oxide TOF turnover frequency (moles epoxide converted per mole of Ti per hour. 

Diphenyl phosphorazidate [DPPA, (Ph0)2P(0)N3l with 4-dimethylaminopyridine (DMAP) and lithium perchlorate opens epoxides regio- and stereo-selectively to yield O-diphenylphosphoryl vicinal azidohydrins see, for example, (15) (16). In the case of O, /3-epoxy ketones and esters, only the corresponding a-azidovinyl ketones and esters were obtained. This is attributed to the acidity of the a-H facilitating dephosphorylation of the initial product. 

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