NHC-Organocatalyzed C Ar -O Bond Cleavage: Mild Access to 2-Hydroxybenzophenones.

Authors :: Janssen-Müller D
Singha S
Lied F
Gottschalk K
Glorius F
Source :: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2017 May 22; Vol. 56 (22), pp. 6276-6279. Date of Electronic Publication: 2017 Jan 27.
Publication Year :: 2017
Abstract: A Truce-Smiles rearrangement of acyl-anion equivalents generated by N-heterocyclic carbene (NHC) catalysis has been achieved. The developed method includes C <subscript>Ar</subscript> -O, C <subscript>Ar</subscript> -S, or C <subscript>Ar</subscript> -N bond cleavage for the formation of a C <subscript>Ar</subscript> -C bond and enables access to 2-hydroxybenzophenones, an important structural motif that is present in several bioactive natural products. By utilizing this procedure, the alkaloid taxilamine was synthesized in three steps. DFT calculations and control experiments support a classical S <subscript>N</subscript> Ar mechanism with a catalyst-bound Meisenheimer-type intermediate. The method features mild reaction conditions, excellent functional-group tolerance, and a broad substrate scope, including various classes of (hetero)arenes.<br /> (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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