Formal [4 + 2] cycloaddition of imines with alkoxyisocoumarinsElectronic supplementary information (ESI) available: Experimental procedures and characterization data. See DOI: 10.1039/c8ob01015c

A new preparation of δ-lactams is reported. In the presence of a Lewis acid promoter, alkoxyisocoumarins engage a range of N -aryl and N -alkyl imines to form δ-lactams with a pendent carboalkoxy substituent. A sulfonamide-thiourea catalyst enables the synthesis of these products in moderate to good enantioselectivities. A new preparation of δ-lactams is reported.