The rhodium carbene route to oxazoles: a remarkable catalyst effect?

Chemical Communications Pub Date: 2009-04-24 DOI: 10.1039/B903878G

Abstract

Dirhodium tetraacetate catalysed reaction of α-diazo-β-keto-carboxylates and -phosphonates with arenecarboxamides gives 2-aryloxazole-4-carboxylates and 4-phosphonates by carbene N–H insertion and cyclodehydration; in stark contrast, dirhodium tetrakis(heptafluorobutyramide) catalysis results in a dramatic change of regioselectivity to give oxazole-5-carboxylates and 5-phosphonates.

Graphical abstract: The rhodium carbene route to oxazoles: a remarkable catalyst effect
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