Accessing benzofuran moieties: A methodological overview of transition-metal-catalysed C–H functionalisation

The wide range of pharmaceutical and biological applications makes the development of efficient and sustainable synthetic strategies for the preparation of benzofuran derivatives an active area of research. Each year, numerous methodologies are reported with the aim of improving the accessibility, selectivity, and atom economy of benzofuran synthesis. In parallel, C–H functionalisation is a powerful tool that enables the direct transformation of straightforward, easily accessible starting materials into complex benzofuran frameworks, minimising the overall input material and the number of synthetic steps required. This review provides a comprehensive overview of advances over the past five years in the synthesis of benzofurans via transition-metal-catalysed C–H functionalisation. Special attention is given to comparing the performance, reactivity, and sustainability of catalysts based on 3d transition metals with those of noble-metal and bimetallic systems.