Combining the Concepts: Dual Catalysis with Carbophilic Lewis Acids

Abstract

Strong together: Both a gold complex and a palladium complex are needed as catalysts in a Stille‐type reaction that does not require an organic halide for the oxidative‐addition step (see scheme; dba=trans,trans‐dibenzylideneacetone). The bimetallic catalyst system facilitates the construction of highly substituted olefins. Additional examples of reactions that employ the combined action of a π acid and a cocatalyst are briefly discussed.

Transition-Metal-Catalyzed Functionalization of C(sp3)&singleBond;H Bonds of Amines

“…40 Combination of organocatalysts and transition-metal catalysts opens a new dimension in organic synthesis. [36,[95][96][97][98] Cooperative metal catalysis and organocatalysis potentially enable transformations that are impossible with a metal catalyst or an organocatalyst alone. An example is the cross-dehydrogenative coupling reaction of glycine esters 137 with unmodified ketones, cooperatively catalyzed by copper(II) acetate and pyrrolidine.…”

Gold/Acid‐Cocatalyzed Regiodivergent Preparation of Bridged Ketals via Direct Bis‐Oxycyclization of Alkynic Acetonides

“…[9] AgOTf cannot be considered as a cocatalyst because its action is generally assumed to be restricted to forming cationic gold species by anion exchange. [10] A possible pathway for the gold/acid-cocatalyzed alkynyldioxolane cyclization may initially involve the formation of a p-complex 3 through coordination of the gold salt to the triple bond of alkynyldioxolanes 1.…”

Lichtgetriebene Ein‐Elektronen‐Transferprozesse als Funktionsprinzip in der Schwefel‐ und Selen‐Multikatalyse

“…Bei genauerer Betrachtung der einzelnen Ausprägungsformen von Multikatalyseprozessen zeigen sich weitere Vorzüge dieser Form der Reaktionsführung (Schema 1). [1,3] So wird bei den am häufigsten anzutreffenden Klassifikationen von Multikatalysen zwischen A) der kooperativen Dualkatalyse [1c, 4] und B) der multifunktionalen Katalyse [1d-f] einerseits sowie C) der gekoppelt-restaurativen Katalyse, [1c] D) der doppelt aktivierenden Katalyse [1e] und E) vielfältigen Formen der Tandemkatalyse [1c] (z. B. Relay-, Kaskaden-und Dominokatalysen) andererseits unterschieden.…”