Banda Saikumar, Johannßen Lasse, Voss Alice, Villinger Alexander, Wenzel Gudrun, Holz Jens, Brasholz Malte
University of Rostock, Institute of Chemistry, Albert-Einstein-Str. 3a, Rostock 18059, Germany.
Leibniz-Institut für Katalyse e.V., Albert-Einstein-Str. 29a, Rostock 18059, Germany.
J Org Chem. 2024 Sep 20;89(18):13263-13271. doi: 10.1021/acs.joc.4c01402. Epub 2024 Sep 6.
Dihydroazepino[1,2-]indole diones are tricyclic -acyl-2-alkylidene-3-oxindole enones that readily engage in tertiary phosphine-catalyzed intermolecular coupling reactions with acceptor-substituted alkenes. In these reactions, the tricyclic α-substituted enones undergo an α-alkylation with concomitant formation of a quaternary stereocenter, as well as the installation of a new double bond within the seven-membered azepane ring. The organocatalytic reaction constitutes a special case of the crossed intermolecular Rauhut-Currier reaction as the presence of the α-substituent in the enones prohibits the formation of an α,β-unsaturated product, but instead, skipped β,γ-unsaturated enones are obtained. With allene carboxylates as alternative coupling partners, the crossed Rauhut-Currier-type reaction competes with a regioselective allene to enone [3 + 2]-cycloaddition, and the product selectivity can be controlled by the choice of the phosphine organocatalyst.
二氢氮杂环庚烷并[1,2 -]吲哚二酮是三环-α-酰基-2-亚烷基-3-氧化吲哚烯酮，它们很容易与受体取代的烯烃发生叔膦催化的分子间偶联反应。在这些反应中，三环α-取代的烯酮发生α-烷基化反应，同时形成一个季碳立体中心，并在七元氮杂环庚烷环内引入一个新的双键。该有机催化反应构成了交叉分子间劳胡特-柯里尔反应的一种特殊情况，因为烯酮中α-取代基的存在阻止了α,β-不饱和产物的形成，而是得到了跳跃的β,γ-不饱和烯酮。以丙二烯羧酸酯作为替代偶联伙伴时，交叉劳胡特-柯里尔型反应与区域选择性丙二烯到烯酮的[3 + 2]环加成反应相互竞争，产物选择性可以通过膦有机催化剂的选择来控制。
