Diastereoselective synthesis of highly functionalized polycyclic benzosultams via tandem cyclisations of cyclic N-sulfonylimines with in situ generated Huisgen 1,4-dipolesElectronic supplementary information (ESI) available: Copies of NMR spectra for all products related to this article; X-ray single crystal structure analysis data for 4aaf. CCDC 1477146. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6ra12771a

Under mild reaction conditions, the tandem cycloadditions of cyclic N -sulfonylimines with in situ generated Huisgen 1,4-dipoles from dialkyl acetylenedicarboxylates and pyridines underwent readily, and delivered highly functionalized polycyclic 1,2,3,4-tetrahydropyrimidine-fused benzosultams in low to excellent chemical yields with excellent diastereoselectivities. The tandem cycloadditions of cyclic N -sulfonylimines with in situ generated Huisgen 1,4-dipoles underwent readily, and delivered 1,2,3,4-tetrahydropyrimidine-fused benzosultams in acceptable chemical yields with excellent diastereoselectivities.