Redox‐Neutral Multicatalytic Cerium Photoredox‐Enabled Cleavage of O−H Bearing Substrates

An approach toward general β C−C bond scission reactions of carboxylic acids and hemiacetals is presented. The present work demonstrates the power of a multicatalytic cerium-based photoredox platform to enable direct hydrodecarboxylation of carboxylic acids as well as redox-neutral ring cleavage of lactol derivatives.

Abstract

The need for synthetic methodologies capable of rapidly altering molecular structure are in high demand. Most existing methods to modify scaffolds rely on net exothermicity to drive the desired transformation. We sought to develop a general strategy for the cleavage of C−C bonds β to hydroxyl groups independent of inherent substrate strain. To this end we have applied a multicatalytic cerium photoredox-based system capable of activating O−H bonds in lactols to deliver formate esters. The same system is also capable of effecting hydrodecarboxylation and hydrodecarbonylation reactions. Initial mechanistic probes demonstrate atomic chlorine (Cl⋅) is generated under the reaction conditions, but substrate activation through cerium-alkoxides or -carboxylates cannot be ruled out.

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