PdII- and PtII-mediated coupling of aryl isocyanides with N-heterocyclic thiones

Abstract

The first example of the addition of an ambident nucleophile's endocyclic center to a coordinated isocyanide is reported, namely, the Pd^II- and Pt^II-mediated reaction of aryl isocyanides with N-methylimidazole- and N-methyltriazole-2-thiones resulting in C,S-chelated deprotonated diaminocarbene complexes. The obtained complexes were isolated in good yields (88–95%) and characterized by elemental analysis (C, H, N), high-resolution mass spectrometry, and IR, 1D (¹H, ¹³C, ¹⁹⁵Pt) and 2D (¹H–¹H COSY, ¹H–¹H NOESY, ¹H–¹³C HSQC, ¹H–¹³C HMBC) NMR spectroscopies, as well as by single-crystal X-ray diffraction for the four complexes. The favorability of the resulting regioselectivity was confirmed by DFT calculations.