2005 Organo-phosphorus compounds S 0080 Regioselective Synthesis of 4- and 5-Oxazole-phosphine Oxides and -phosphofrom 2H-Azirines and Acyl Chlorides. — Addition of acyl chlorides to phos02- 174 nates phorylated azirines leads to N-acylated products which can undergo regioselective ring-opening at C1 or C2 to afford vinylamides or vinylogous α-amidophosphorus compounds. Base treatment of the latter provides a simple, mild, and convenient approach to 5- and 4-phosphorylated oxazoles, respectively. Reaction of the phenyl azirines (VIII) with acetyl chloride directly gives the oxazoles (IX). The products are of synthetic and biological interest. — (PALACIOS*, F.; OCHOA DE RETANA, A. M.; GIL, J. I.; ALONSO, J. M.; Tetrahedron 60 (2004) 40, 8937-8947; Dep. Quim. Org., Fac. Farm., Univ. Pais Vasco, E-01080 Vitoria, Spain; Eng.) — Jannicke 2005
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