The development of metal-catalysed methods to functionalize inert C-H bonds has become a dominant research theme in the past decade as an approach to efficient synthesis. However, the incorporation of carbon monoxide into such reactions to form valuable ketones has to date proved a challenge, despite its potential as a straightforward and green alternative to Friedel-Crafts reactions. Here we describe a new approach to palladium-catalysed C-H bond functionalization in which carbon monoxide is used to drive the generation of high-energy electrophiles. This offers a method to couple the useful features of metal-catalysed C-H functionalization (stable and available reagents) and electrophilic acylations (broad scope and selectivity), and synthesize ketones simply from aryl iodides, CO and arenes. Notably, the reaction proceeds in an intermolecular fashion, without directing groups and at very low palladium-catalyst loadings. Mechanistic studies show that the reaction proceeds through the catalytic build-up of potent aroyl triflate electrophiles.

Synthesis of t BuC≡C(CH 2 ) 4 C≡C t Bu. Under a nitrogen atmosphere, a 1.6 M solution of n BuLi in hexanes (37.5 mL, 60 mmol) was added dropwise to a chilled (−78 °C) solution of tbutylacetylene (4.76 g, 58 mmol) in 60 mL of THF. The resulting mixture was stirred at −78 °C for 20 min and then warmed to room temperature. 1,4-Dibromobutane (3.34 mL, 28 mmol) and hexamethylphosphoramide (HMPA, 20 mL) were added sequentially and the reaction mixture was stirred at room temperature for another 4 h before it was diluted with 100 mL of water. The organic layer was separated and the aqueous layer was extracted with diethyl ether (40 mL × 3).The combined organic layers were dried over Na 2 SO 4 , filtered, and concentrated under vacuum.The diyne product was purified via vacuum distillation (52-56 °C/0.1 mmHg) and isolated as a

We report a new strategy for the conversion of carboxylic acids into potent acid triflate electrophiles. The reaction involves oxidative carbonylation of carboxylic acids with I2 in the presence of AgOTf, and is postulated to proceed via acyl hypoiodites that react with CO to form acid triflates. Coupling this chemistry with subsequent trapping with arenes offers a mild, room temperature approach to generate ketones directly from broadly available carboxylic acids without the use of corrosive and reactive Lewis or Bronsted acid additives, and instead from compounds that are readily available, stable, and functional group compatible.

We report a new strategy for the conversion of carboxylic acids into potent acid triflate electrophiles. The reaction involves oxidative carbonylation of carboxylic acids with I2 in the presence of AgOTf, and is postulated to proceed via acyl hypoiodites that react with CO to form acid triflates. Coupling this chemistry with subsequent trapping with arenes offers a mild, room temperature approach to generate ketones directly from broadly available carboxylic acids without the use of corrosive and reactive Lewis or Bronsted acid additives, and instead from compounds that are readily available, stable, and functional group compatible.

A palladium catalyzed route to prepare aryl ketones from their two fundamental building blocks, two arenes and carbon monoxide, is described.