A mild, practical and efficient palladium-catalyzed decarboxylative ortho-acylation of O-methyl ketoximes with a-keto acids via C-H bond activation is described. In these reactions, a broad range of Omethyl ketoximes and a-keto acids undergoes the decarboxylative cross-coupling reactions with high selectivities and good tolerance. Aryl ketones are important structural motifs found in natural products, medicinally relevant molecules, and functional materials. 1 In particular, 1,2-diacylbenzenes

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... re known to be crucial synthetic precursors to construct a wide range of biologically active compounds including phthalazines, phthalimidines, isobenzofuranes, indanones, isoindoles, and isoindolines. 2 These facts have led to increasing interest in developing an efficient method for the preparation of 1,2-diacylbenzenes. Traditional metal-catalyzed crosscoupling reactions between aryl metal reagents and aryl halides are well-established methods for carbon-carbon bond formations. 3 Recently, transition-metal-catalyzed decarboxylative cross-coupling reactions using aryl carboxylic acids as coupling partners have emerged as a promising set of carbon-carbon bond formation reactions. 4 In these reactions, readily available carboxylic acids enable decarboxylative cross-coupling reactions to proceed with high selectivities and tolerance of functional groups. Therefore, decarboxylative cross-coupling reactions provide new alternatives for Mirozoki-Heck type reactions, 5 oxidative arylation, 6 redox-neutral biaryls synthesis, 7 and allylation. 8 Recently, directinggroup-assisted activation of aromatic ortho-C-H bonds, and subsequent acylation reaction by coupling with aldehydes or alcohols have been reported. 9 A variety of directing groups, such as pyridines, 10 amides, 11 oximes, 12 acetanilides, 13 and indole, 14 have been used for C-H bond activation. However, decarboxylative acylations of aromatic C-H bonds using a-keto acids as acyl surrogates were relatively unexplored. Goossen et al. first demonstrated a Pd-catalyzed decarboxylative acylation of aryl bromides with a-keto carboxylate salts as acyl anion equivalents to afford diaryl ; Fax: +82 31 292 8800; Tel: +82 31 290 7788 † Electronic supplementary information (ESI) available: Experimental details and spectroscopic data for all compounds. See