Remote carboxylation of halogenated aliphatic hydrocarbons with carbon dioxide

Abstract

Catalytic carbon-carbon bond-formation has allowed for the streamline of synthetic routes when assembling complex molecules. This is particularly important when incorporating saturated hydrocarbons, common motifs in petrochemicals and biologicallyrelevant molecules. However, cross-coupling methods involving alkyl electrophiles occur at specific and previously functionalised sites. Herein, we describe the discovery of a catalytic method capable of promoting carboxylation reactions at remote and unfunctionalised aliphatic sites under atmospheric pressure of CO2. The reaction occurs via selective migration of the catalyst along the hydrocarbon side-chain and operates with excellent regio- and chemoselectivity profile. Our results demonstrate that site-selectivity can be switched and controlled, allowing for the functionalisation of less-reactive positions in the presence of a priori more reactive ones. Furthermore, we show that raw materials obtained in bulk from petroleum processing, such as alkanes and unrefined mixtures of olefins, can be used as substrates. This constitutes a unique opportunity to integrate a catalytic platform en route to valuable fatty acids by direct transformation of petroleum-derived feedstocks. We anticipate that our methodology will have a broad impact in the preparation of carboxylic acids from simple chemical feedstocks, and will lead to new knowledge in synthetic design when targeting the controlled functionalisation of saturated hydrocarbon chains.