Diazo chemistry in the access to novel fatty acids linked to spiro-fused oxetane-pyrazolone scaffold

A novel free fatty acid mimetic based on the spirocyclic oxetane pyrazolone 1-oxa-6,7-diazaspiro[3.4]oct-7-en-5-one scaffold has been obtained in seven steps. The key stages are based upon the toolbox of diazo chemistry, including the F SAFE diazo transfer and Rh^II-catalyzed O–H insertion followed by base-triggered oxetane closing.