Lewis-base stabilized diiodine adducts with N-heterocyclic chalcogenamides

Abstract

Oxidation reactions of stable chalcogenamides with iodine are intriguing due to their broad application in various organic syntheses. In the present study we report on the utilization of N-heterocyclic carbene and cyclic-alkyl-amino carbenes L^1–3: (L¹: = :C[N(2,6-iPr₂-C₆H₃)CH]₂, L²: = :C(CH₂)(CMe₂)(C₆H₁₀)N-2,6-iPr₂-C₆H₃, L³: = :C(CH₂)(CMe₂)₂N-2,6-iPr₂-C₆H₃) for the syntheses of chalcogenamides L^1–3E (E = S, Se, Te) 1–4 and zwitterionic adducts L^1–3E–I–I 5–8. The synthesis of compounds 1–4 involved the addition reaction of ligand L^1–3: and elemental chalcogen. Treatment of 1–4 with iodine resulted in the formation of adducts 5–8. Compounds 5–8 are well characterized with various spectroscopic methods and single-crystal X-ray structural analysis.