An organocatalytic asymmetric reaction between 5H-oxazol-4-ones and N-substituted maleimides is disclosed. Employing Takemoto's chiral tertiary amine-thiourea as the catalyst, [4 + 2] annulation reactions were performed with high chemoselectivity, leading to a series of biologically important chiral oxo-bridged piperidone-fused succinimides in good to excellent enantioselectivities (up to >99% ee) and >19:1 dr.
Bibliographical noteFunding Information:
We are grateful for the grants from NSFC (21072044) and Henan province (14IRTSTHN006, 152300410057, 162300410002).
© 2016 American Chemical Society.