Formation of azarhodacyclobutanes with varying N-substitution

Oxidation of the rhodium(I) ethylene complex, [(TPA) Rh(eta(2)-CH2CH2)](+) (1, TPA = N, N, N-tris(2-pyridylmethyl) amine) with a selection of nitrene precursors led to formation of N-substituted azarhodacyclobutanes. Appropriate choice of oxidant allowed for selective preparation of one isomer. For example, treatment of 1 with tosyl azide provided isomer 3 exclusively for the first time. Variation of the substituent on the ring-nitrogen was possible e.g., by employing nosyl iodinane precursor 8. Substituted carbamates were also screened, providing two rotamers of isomer type 3. In addition, preliminary reactivity studies revealing the increased chemical reactivity of the product complexes 14 and 15 are presented. (C) 2015 Elsevier B.V. All rights reserved.