Diversity-oriented synthesis of heterocycles and macrocycles by controlled reactions of oxetanes with α-iminocarbenes† †Electronic supplementary information (ESI) available: Synthetic protocols, 1H/13C NMR and HR mass spectra are provided. CCDC 1443618–1443620 and 1534812–1534815. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc00964j Click here for additional data file. Click here for additional data file.

Using N-sulfonyl triazoles as substrates, compounds as diverse as 2-imino tetrahydrofurans, 13and 15membered ring aza-macrocycles can be prepared selectively via formal [1 + 4], [5 + 4 + 4] and [3 + 4 + 4 + 4] condensations of a-imino carbenes and oxetanes under Rh(II)-catalysis or thermal activation. Spirocyclic N-heterocycles are also accessible by means of Buchwald–Hartwig and Pictet–Spengler cyclizations. By reaction control, substrate selection or further derivatization, a large variety of chemical structures is thus achievable. Finally, using triazoles reacting under thermal activation, interesting mechanistic insight was obtained.