A new stereoselective entry to novel, chiral fused-carbocycle uracils

Herein we report a new asymmetric, vinylogous,[1] dearomative [4+2] cycloaddition reaction between remotely enolizable, nitrogen-protected uracil-5-carbaldheydes[2] and β-nitrostyrene unlocking the access to a new series of highly-functionalized, enantioenriched fused-uracil hetero-bicycles with three contiguous stereocentres. The stereochemical fate of the reaction is orchestrated by a chiral, bifunctional thiourea organocatalyst through a non-covalent catalysis approach. The reaction denote excellent diastereoselectivities and good enantioselectivities for all catalytic nitro-adducts. Moreover, it is demonstrate the possibility to provide enantiopure products by a resolution by re-crystallization consisting of one single cycle. Finally, the possibility to reduce the nitro-group is illustrated.