Transition Metal‐Free Carbonylation Processes

Carbonylation processes with carbon monoxide as a carbonyl source generally require the employment of a transition metal and an expensive ligand (often organophosphine or N -heterocyclic carbene) to ensure high efficiency. However, this transition-metal catalysis may present several limitations, such as the cost of the transition-metal catalyst, deactivation of the catalyst (CO is a strong π-acidic ligand), and generation of residual metal contamination. Therefore, efficient and practical strategies devoid of metal catalysts are highly desirable and represent a formidable challenge. The important advances in transition-metal-free carbonylation with carbon monoxide as carbonyl source for synthesizing aldehydes and ketones, esters and lactones, amides, acids and anhydrides, and chloride and alcohols are reviewed in this chapter. This would be useful for synthetic organic chemists and inspire further reaction development in the transition-metal-free carbonylation area.