Switchable Selectivity in the Pd-Catalyzed Alkylative Cross-Coupling of Esters

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Palladium-catalyzed cross-coupling reactions are crucial in organic synthesis.
• Activation of the C(acyl)-O bond in phenyl esters presents synthetic challenges.
• Developing selective and divergent catalytic systems is highly desirable.

Purpose of the Study:

• To disclose a novel Pd-catalyzed cross-coupling reaction between phenyl esters and alkyl boranes.
• To demonstrate catalyst-controlled selective synthesis of two distinct product classes.
• To explore the applications and mechanistic basis of this divergent strategy.

Main Methods:

• Utilizing palladium catalysts with different ligands (N-heterocyclic carbene (NHC) and 1,5-cyclooctadiene-based phosphine (dcype)).
• Reacting phenyl esters with alkyl boranes under varying catalytic conditions.
• Employing Suzuki-Miyaura reaction conditions and a modified pathway involving CO extrusion.

Main Results:

• Selective synthesis of alkyl ketones via Suzuki-Miyaura coupling with a Pd-NHC catalyst, activating the C(acyl)-O bond.
• Selective synthesis of alkylated arenes via a modified pathway with a Pd-dcype catalyst, involving CO extrusion.
• Achieved good yields for both product types, demonstrating a divergent coupling strategy.

Conclusions:

• A versatile Pd-catalyzed cross-coupling method for phenyl esters and alkyl boranes has been developed.
• Switchable selectivity between alkyl ketone and alkylated arene formation is achieved by catalyst choice.
• The study provides insights into catalyst-controlled reactivity and potential synthetic applications.