Synthesis of α-(4-Oxazolyl)amino Esters via Brønsted Acid Catalyzed Tandem Reaction
作者:Ansoo Lee、Seohee Oh、Hyunwoo Kim
DOI:10.1021/acs.orglett.8b01212
日期:2018.6.1
A one-step, Brønsted acid catalyzed tandem reaction for the synthesis of α-(4-oxazolyl)amino esters was developed. 4-Nitrobenzenesulfonic acid was found to be an efficient catalyst for the coupling of ethyl 2-oxobut-3-ynoates with amides to provide various α-(4-oxazolyl)amino esters. The experimental and X-ray crystallographic data suggest that a series of bond-forming reactions including imine formation
A new synthesis of alpha-quaternary alkynyl amino esters and allenoates was developed utilizing umpolung N-addition to beta,gamma-alkynyl alpha-imino esters followed by regioselective acylation. The reaction exhibits broad substrate generality and unique regioselectivity. Moreover, synthesis of alpha-quaternary alkynyl amino esters was also carried out via oxidation of the intermediary enolate followed by alkylation.