The reductive C3 functionalization of pyridinium and quinolinium salts through iridium-catalysed interrupted transfer hydrogenation.

Autor: Grozavu A; Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK., Hepburn HB; Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK., Smith PJ; Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK., Potukuchi HK; Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK., Lindsay-Scott PJ; Eli Lilly and Company Limited, Erl Wood Manor, Windlesham, Surrey, UK., Donohoe TJ; Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK. timothy.donohoe@chem.ox.ac.uk.
Jazyk: angličtina
Zdroj: Nature chemistry [Nat Chem] 2019 Mar; Vol. 11 (3), pp. 242-247. Date of Electronic Publication: 2018 Dec 17.
DOI: 10.1038/s41557-018-0178-5
Abstrakt: Aromatic rings are ubiquitous in organic chemistry and form the basis of many commercial products. Despite the numerous routes available for the preparation of aromatic compounds, there remain few methods that allow their conversion into synthetically useful partially saturated derivatives and even fewer that allow new C-C bonds to be formed at the same time. Here we set out to address this problem and uncover a unique catalytic partial reduction reaction that forms partially saturated azaheterocycles from aromatic precursors. In this reaction, methanol and formaldehyde are used for the reductive functionalization of pyridines and quinolines using catalytic iridium; thus, inexpensive and renewable feedstocks are utilized in the formation of complex N-heterocycles. By harnessing the formation of a nucleophilic enamine intermediate, the C-C bond-forming process reverses the normal pattern of reactivity and allows access to the C3 position of the arene. Mechanistic investigations using D-labelling experiments reveal the source of hydride added to the ring and show the reversible nature of the iridium-hydride addition.
Databáze: MEDLINE
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