Palladium‐Catalyzed Oxidative Synthesis of α‐Acetoxylated Enones from Alkynes

Abstract

We report apalladium-catalyzed oxidative functionalization of alkynes to generate a-acetoxylated enones in one step.Arange of functional groups are well-tolerated in this reaction. Mechanistic studies,i ncluding the use of 18 O-labeled DMSO,r evealed that the ketone oxygen atom in the product originates from DMSO. AngewandteChemie Communications Scheme 3. Acetoxylation of substrates with different aryl substituents. Reactionsw ere carried out on a0 .3 mmol scale. Yields are for the isolated product. [a] Reaction time:4 0h.Scheme 4. Reactions of 1a with PhI(OPiv) 2 or [ 18 O]DMSO. Scheme 5. Isotope-labeling experiments. Angewandte Chemie Communications 5826 www.angewandte.org Scheme 7. Asymmetric hydrogenation of a-acetoxylated enones. tAmOH = 2-methyl-2-butanol, cod = 1,5-cyclooctadiene. Scheme 6. Proposed reaction mechanism. Angewandte Chemie Communications

N‐Directed Pd‐Catalyzed Direct ortho‐Acetoxylation and ortho‐tert‐Butoxylation of 2‐Phenyl‐4H‐benzo[d][1,3]oxazin‐4‐ones via C‐H Activation

“…Moreover, functional group assisted selective acetoxylation of inert C−H bonds of an aryl system with the help of transition metal catalyst has proven to be a highly diligent approach for the direct construction of C−O bonds …”