Catalytic CO homologation at magnesium

The synthesis of C2+ molecules from C1 sources is a critical technology for a sustainable chemical economy. Carbon monoxide (CO) is a key C1 feedstock for processes such as the Fischer-Tropsch synthesis, however achieving the reductive coupling of CO to C2+ products with selectivity is a major contemporary challenge. Homogeneous catalysis has been proposed to address this gap though this is largely unrealised despite nearly half a century of research. This report details the homologation of CO catalysed by a dipyrromethene magnesium alkyl complex, and a turnover strategy underpinned by the bulk industrial reagent triethylaluminium. Single turnover experiments between the magnesium alkyl catalyst and CO resulted in a CO homologated product. Reaction of this product with triethylaluminium allowed for isolation of intermediates and provided experimental evidence for structural motifs in the calculated catalytic pathway. This work demonstrates a new approach to CO activation and catalysis mechanistically distinct from transition-metal reactivity.