Catalytic Diastereo- and Enantioselective Synthesis of 2Imidazolinones [component]

Chiral cyclic ureas (2-imidazolinones) were prepared by the reaction of nitrones and isocyanoacetate esters using a multicatalytic system that combines a bifunctional Brønsted base-squaramide organocatalyst and Ag + as Lewis acid. The reaction could be achieved with a range of nitrones derived from aryl-and cycloalkylaldehydes with moderate diastereo-and good enantioselectivity. A plausible mechanism involving an initial formal [3+3] cycloaddition of the nitrone and isocyanoacetate ester,
more » ... cetate ester, followed by rearrangement to an aminoisocyanate and cyclization to the imidazolinone is proposed.
doi:10.1021/acs.orglett.9b01244.s001 fatcat:g5emgbgc7zauhhmzy2qfbkanoe