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Metal-catalysed C-H bond functionalization has received tremendous attention and developed rapidly over the past decades. Cyclopentadienyl (Cp) metal complexes and their asymmetric counterparts (CpX) are part of a central organometallic category empowering challenging transformations. However, the established preparation of d9 metal CpX precatalysts is restricting despite their recognised usefulness. At the same time, constant progressing in cutting-edge and challenging transformations is essential. For example, atropselective reactions and alkynyl C-H bond activations are far less developed that C(sp2)-H analogues. A novel approach to metal-Cp ligand bond generation under mild conditions and additionally tolerating air and water is disclosed in this thesis. The complexation method generates non C2-symmetric complexes, which are then suitable for in-situ complexation comparable to previously reported asymmetric transformations. Engaging alpha-arylated cyclopropyl hydroxamids with a Rh(III)-catalyst gave rise to a ring expansion providing gamma-lactams decorated with a quaternary centre. Mechanistically, the multicomponent transformation proceeds via an unusual C-H/C-C bond activation sequence. Moreover, an atropselective synthesis was investigated to deliver unreported 5,6-heterobiaryls which would serve as analogues of MOP ligands after derivatization.
Nicolai Cramer, Matthew Wodrich, Miyeon Chang, Simone Gallarati
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