The rhodium carbenoid route to oxazoles. Synthesis of 4-functionalised oxazoles; three step preparation of a bis-oxazole

Article abstract of DOI:10.1016/S0040-4020(01)90396-5

Oxazole-4-sulfones, -phosphonates, and -nitriles are prepared by rhodium(II) catalysed addition of nitriles to the corresponding diazo compound. The effect of the ligand on rhodium was briefly investigated, with rhodium(II) trifluoroacetamide generally proving the most effective catalyst. The 4-cyanooxazole 9 is readily converted into the bis-oxazoles 10-12.