First Synthesis of β-Keto Sulfoxides by a Palladium-Catalyzed Carbonylative Suzuki Reaction

Abstract

[reaction: see text] An unprecedented palladium-catalyzed three-component cross-coupling reaction between alpha-bromo sulfoxide, carbon monoxide, and aromatic boronic acids provides a new and efficient approach to the synthesis of beta-ketosulfoxides. The reaction takes place under mild conditions with a wide range of variously substituted aryl and heteroaryl boronic acids. The carbonylative cross-coupling reaction is strongly favored over competing direct cross-coupling and homocoupling processes, except with boronic acids carrying strong electron-withdrawing substituents.

Palladium‐Catalyzed Carbonylation Reactions of Aryl Halides and Related Compounds

“…The first synthesis of b-keto sulfoxides by a palladiumcatalyzed carbonylative Suzuki reaction. [102] yield and selectivity at 5 bar CO. Dibromopyridines furnished the corresponding dibenzoylpyridines when [PdCl 2 (PCy 3 ) 2 ] was used. [103,104] Shortly afterwards, the authors succeeded in extending the scope of the reaction to chloropyridines and chloroquinoline.…”

“…b-Ketosulfoxides 108 were synthesized for the first time by transformation of a-bromo sulfoxide 107 with (hetero)aryl boronic acids under atmospheric CO pressure (Scheme 28). [102] Neither homo-and cross-coupling side products nor sulfoxides resulting from dehalogenation were observed in significant amounts. Under mild conditions, aryl boronic acids with electron-withdrawing substituents were less reactive, and alkyl boronic acids did not react at all.…”

“…A modified reaction mechanism was suggested for the Suzuki carbonylation of a-bromo sulfoxides. [102] Castanet and co-workers introduced [PdCl 2 (PPh 3 ) 2 ] [103,104] as an efficient catalyst for carbonylative Suzuki crosscoupling reactions of 2-or 4-substituted iodo-and bromopyridines. Thus, phenyl pyridyl ketones were obtained in high Figure 8.…”

Transition metals in organic synthesis: Highlights for the year 2005

“…A palladium-catalyzed carbonylative coupling of phenyl bromomethyl sulfoxide with aryl boronic acids to give ␤-keto sulfoxides was reported [513]. Palladium-catalyzed carbonylative couplings of alkenyl triflates with alkenyl tin reagents were used in synthesis of C(1-4)-linked disaccharides [514].…”

Palladiumkatalysierte Carbonylierungen von Arylhalogeniden und ähnlichen Substraten

“…Die β‐Ketosulfoxide 108 wurden zum ersten Mal aus α‐Bromsulfoxid 107 und (Hetero‐)Arylboronsäuren unter 1 bar CO synthetisiert (Schema ) 102. Es wurde keine Bildung signifikanter Mengen an Nebenprodukten (durch die entsprechende Homo‐ oder Kreuzkupplung oder durch Dehalogenierung zu den Sulfoxiden) beobachtet.…”