Palladium-catalyzed oxidative difunctionalization of alkenes with α-carbonyl alkyl bromides initiated through a heck-type insertion: A route to indolin-2-ones

Article abstract of DOI:10.1002/anie.201402893

The oxidative interception of various σ-alkyl palladium(II) intermediates with additional reagents for the difunctionalization of alkenes is an important research area. A new palladium-catalyzed oxidative difunctionalization reaction of alkenes with α-carbonyl alkyl bromides is described, in which the σ-alkyl palladium(II) intermediate is generated through a Heck insertion and trapped using an aryl C(sp²)-H bond. This method can be applied to various α-carbonyl alkyl bromides, including primary, secondary, and tertiary α-bromoalkyl esters, ketones, and amides. Indolinone synthesis: A new palladium-catalyzed oxidative difunctionalization reaction of N-arylalkenes with primary, secondary, and tertiary α-carbonyl alkyl bromides proceeds through a radical process and provides indolin-2-ones in moderate to excellent yields. The reaction is initiated by a Heck insertion followed by interception of the σ-alkyl palladium(II) intermediate with aryl C(sp²)-H bonds. dppe=1,2-bis(diphenylphosphino)ethane.