Synlett 2024; 35(09): 967-972
DOI: 10.1055/a-2225-8736
cluster
Chemical Synthesis and Catalysis in Germany

Aromatic Amine Catalysts for the O2-Mediated Cross-Dehydrogenative Phenothiazination Reaction?

Shiny Nandi
,
Alina Paffen
,
Frederic W. Patureau
The DFG-funded transregional collaborative research center SFB/TRR 88 ‘Cooperative effects in homo and heterometallic complexes’ (http://3MET.de) is gratefully acknowledged for financial support.


Abstract

Metal-free aromatic amines have been utilized recently as redox-active catalysts in various oxidative coupling reactions. In this study, we investigated a series of aromatic amines and their potential redox catalytic activity, in particular compared to our previously reported amino-Te(II) catalysts. The O2-mediated cross-dehydrogenative phenothiazination of phenols was utilized as a benchmark test reaction, as well as the O2-mediated cross-dehydrogenative coupling of indoles. We thus identified a proton sponge as an effective aromatic amine redox catalyst. It was moreover found that although the proton sponge displays clear catalytic activity, it is generally less active than previously reported phenotellurazine catalysts. The insights provided by this study should guide future research efforts for the development of innovative redox-catalyzed cross-dehydrogenative coupling reactions.

Supporting Information



Publication History

Received: 04 September 2023

Accepted after revision: 11 December 2023

Accepted Manuscript online:
11 December 2023

Article published online:
09 February 2024

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