AUTHOR=Gallo Rafael D. C. , Campovilla Jr. Orlando C. , Ahmad Anees , Burtoloso Antonio C. B. 

TITLE=Synthesis of Oxazinanones: Intramolecular Cyclization of Amino Acid-Derived Diazoketones via Silica-Supported HClO4 Catalysis

JOURNAL=Frontiers in Chemistry

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00062

DOI=10.3389/fchem.2019.00062

ISSN=2296-2646

ABSTRACT=<p>A Brønsted acid catalyzed intramolecular cyclization of <italic>N</italic>-Cbz-protected diazoketones, derived from α-amino acids, is described. The reaction proceeds under metal-free conditions and is promoted by ecofriendly silica-supported HClO<sub>4</sub> as the catalyst and methanol as the solvent. This transformation enables the short synthesis of various 1,3-oxazinane-2,5-diones under mild reaction conditions and in good yields (up to 90%). The set-up is very simple; by just mixing all reagents together with no work-up necessary before purification, this protocol takes a greener approach.</p>