A Direct Organocatalytic Enantioselective Route to Functionalized trans-Diels-Alder Products Having the Norcarane Scaffold.

Autor: Barløse CL; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Østergaard NL; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Bitsch RS; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Iversen MV; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Jørgensen KA; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2021 Aug 09; Vol. 60 (33), pp. 18318-18327. Date of Electronic Publication: 2021 Jul 09.
DOI: 10.1002/anie.202106598
Abstrakt: An enantioselective methodology to construct trans-Diels-Alder scaffolds by organocatalysis with excellent selectivity, high yield and up to five contiguous stereocenters is presented. The reaction concept integrates the halogen effect and a novel discovered pseudo-halogen effect to direct an endo-selective, secondary-amine catalyzed Diels-Alder reaction allowing for the subsequent formation of trans-Diels-Alder cycloadducts featuring the norcarene scaffold. The methodology relies on the reaction between an in situ generated trienamine and an α-brominated or α-pseudo-halogenated enone to form a fleeting cis-Diels-Alder intermediate. The endo-transition state-enhanced by the (pseudo-)halogen effect-sets the stereochemistry that allows for a subsequent S N 2-like reaction at a tertiary center to obtain the trans-Diels-Alder scaffold. The mechanism was investigated and supported by experimental results as well as computational studies.
(© 2021 Wiley-VCH GmbH.)
Databáze: MEDLINE
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