Synthesis of 4‐Alkenyl Benzoxazoles via Pd‐catalyzed ortho C−H Functionalization of 2‐Amidophenols

Abstract

A one-pot direct transformation to remotely CÀH alkene functionalized 2-aryl benzoxazoles from the reaction of amidophenol and electronically deficient olefin was reported. Control experiments confirm that the Pd-catalyzed regioselective CÀH activation/alkenylation occurs at the first step by leading to ortho-alkenylated amidophenol; which subsequently underwent tandem intramolecular annulation to afford C4-alkenylated 2arylbenzoxazole derivatives.

Palladium‐Catalyzed ortho‐Benzoylation of Sulfonamides through C−H Activation: Expedient Synthesis of Cyclic N‐Sulfonyl Ketimines

“…In continuation of our current research on TMcatalyzed cross-coupling reactions, [11] we became interested to develop an efficient method for ortho-carbonylation of sulfonamides through CÀ H bond activation. Herein, we report the Pd-catalyzed dehydrogenative coupling of N-methoxy sulfonamides with aryl aldehydes to produce o-keto sulfonamides.…”

“…Though the Nacylation of sulfonamide using aldehyde has already been delineated; [10] to the best of our knowledge, [5,8] sulfonamide directed ortho-carbonylation using carbaldehyde precursor has remained elusive in the literature. In continuation of our current research on TMcatalyzed cross-coupling reactions, [11] we became interested to develop an efficient method for ortho-carbonylation of sulfonamides through CÀ H bond activation. Herein, we report the Pd-catalyzed dehydrogenative coupling of N-methoxy sulfonamides with aryl aldehydes to produce o-keto sulfonamides.…”

Tunable Single and Double γ‐C−H Arylation of Phenylacetamides Directed by o‐Aminophenols

“…Aryl iodides functionalized with electron donating (4 b-d, 4 As outlined in Scheme 2, the selective synthesis of single arylated phenylacetamides 4 displayed excellent scope to both substrates.…”

“…Recently, the simple OAPs have been identified as practical DG precursors in a series of different CÀ H activation reactions. [4] In despite of these inspiring works, more different CÀ H bond activation reactions assisted by such DGs are yet to explore. [2] Later on, this DG was found as effective fragment in assisting the tandem CÀ H olefination and intramolecular hydroamination for the synthesis of isoindolinones with Rh-/Cu-cocatalyst system.…”

“…[3] Rather recently, Panda and Sahoo developed the tandem synthesis of alkenyl functionalized benzoxazoles via a key CÀ H alkenylation with palladium catalysis using OAP-functionalized benzamides. [4] In despite of these inspiring works, more different CÀ H bond activation reactions assisted by such DGs are yet to explore.…”