Diverse Trifluoromethyl Heterocycles from a Single Precursor

Ethyl 2-diazo-4,4,4-trifluoro-3-oxobutanoate is a highly
versatile
intermediate for the synthesis of a wide range of trifluoromethyl
heterocycles. With the use of rhodium­(II) or copper­(II) catalyzed
carbene X–H insertion reactions as key steps, a diverse set
of trifluoromethyl-oxazoles, -thiazoles, -imidazoles, -1,2,4-triazines,
and -pyridines are available from the diazoketoester, either directly
in a single step or with just one additional step.