keto carbenes

https://doi.org/10.1351/goldbook.K03385
The term has imprecisely been used to designate carboxylic @A00121@. @K03382@ @C00806@ are @C00806@ bearing an oxo function at an unspecified site.
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1345 [Terms] [Paper]