The Synthesis of Heterocyclic Compounds Starting from Lactones, Lactams, and Thiollactones¹

Lactones, lactams, and thiollactones, both unsubstituted and containing reactive substituents, are useful starting materials in the synthesis of various types of heterocyclic organic compounds. The use of suitably substituted lactones, lactams, and thiollactones is particularly favorable in the synthesis of polycyclic heterocyclic systems. The principal reactions are illustrated by selected examples. 1. Heterocyclic Compounds from Unsubstituted γ-Lactones 2. Heterocyclic Compounds from Lactones Containing Simple Substituents 3. Heterocyclic Compounds from Lactones, Lactams, and Thiollactones Containing Reactive Substituents 3.1. Synthesis and Rearrangement of α-Acyllactones, α-Acyllactams, and α-Acyl-thiollactones 3.2. Subsequent Reactions with Rearranged Products Obtained as in 3.1. 3.3. Heterocyclic Compounds from Acyllactones, Acyllactams, and Acyl-thiollactones by Reaction with Nucleophilic Bases 4. Heterocyclic Compounds from α-Methylenelactones, α-Methylenelactams, and α-Methylene-thiollactones (Zimmer Rearrangement) 5. Heterocyclic Compounds from Reactive Lactams