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=Volume 7 - 2019

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=A Brønsted acid catalyzed intramolecular cyclization of N-Cbz-protected diazoketones, derived from α-amino acids, is described. The reaction proceeds under metal-free conditions and is promoted by ecofriendly silica-supported HClO4 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%). Set-up is very simple by just mixing all reagents together and no work-up is necessary before purification, making this protocol a greener approach.