The highly reactive nature of acid chlorides distinguishes them as desirable reagents for a host of substitution reactions utilizing transition metal-catalyzed carbon-carbon bond formation or heteroatomic nucleophiles. However, many of the established methods for acid chloride preparation require vigorous conditions like thionyl chloride, phosphorous pentachloride, or oxalyl chloride and result in the generation of acidic by-products. Additionally, the highly reactive nature of the acid chloride often renders purification problematic. The combination of triphenylphosphine and carbon tetrachloride (PPh3/CCl4) forms an intermediate phosphorane, which is an excellent chlorinating reagent for both alcohols and carboxylic acids. Numerous studies have detailed the application of this chemistry to the synthesis of a variety of acyl derivatives like amides and esters, but none have investigated its application to the synthesis of carbon-carbon bonds. Initial studies from our lab have demonstrated that treatment of a carboxylic acid with PPh3/CCl4 in acetonitrile followed by a Pd0 catalyst and a stannane in a tandem reaction sequence directly gives a ketone in one pot. This presentation will detail those results.

Synthesis of ketones from carboxylic acids using a convenient, one-pot protocol

247th National Meeting (2014)

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