Synthesis of Lactams via Isocyanide-Based Multicomponent Reactions

Abstract Lactams are very important heterocycles as a result of their presence in a wide range of bioactive molecules, natural products and drugs, and also due their utility as versatile synthetic intermediates. Due to these reasons, numerous efforts have focused on the development of effective and efficient methods for their synthesis. Compared to conventional two-component reactions, multicomponent reactions (MCRs), particularly isocyanide-based MCRs, are widely used for the synthesis of a range of small heterocycles including lactam analogues. Despite their numerous applications in almost every field of chemistry, as yet there is no dedicated review on isocyanide-based multicomponent reactions (IMCRs) concerning the synthesis of lactams. Therefore, this review presents strategies towards the synthesis of α-, β-, γ-, δ- and ε-lactams using IMCRs or IMCRs/post-transformation reactions reported in the literature between 2000 and 2020. 1 Introduction 2 Developments in Lactam Synthesis 2.1 α-Lactams 2.2 β-Lactams 2.3 γ-Lactams 2.3.1 General γ-Lactams 2.3.2 Benzo-Fused γ-Lactams 2.3.3 Spiro γ-Lactams 2.3.4 α,β-Unsaturated γ-Lactams 2.3.5 Polycyclic Fused γ-Lactams 2.4 δ-Lactams 2.5 ε-Lactams 3 Conclusions