One-Pot Cyclizations of (2,4-Dioxobutylidene)phosphoranes and (2-Alkoxy-4-oxobut-2-enylidene)phosphoranes

Abstract

(2,4-Dioxobutylidene)phosphoranes and (2-alkoxy-4-oxobut-2-enylidene)phosphoranesare readily available and represent versatile building blocks inone-pot cyclizations. Their reactions with various electrophiles,such as 1,3-dicarbonyl compounds, enones, α-halo ketones,or hydrazine derivatives, allow a convenient synthesis of a varietyof carbocyclic and heterocyclic ring systems. 1 Introduction 2 (2,4-Dioxobutylidene)phosphoranes 2.1 Synthesis 2.2 Cyclization Reactions 2.2.1 Formation of Five-Membered Carbacycles 2.2.2 Formation of Six-Membered Carbacycles 2.2.3 Formation of Seven-Membered Carbacycles 2.2.4 Formation of Heterocycles 3 (2-Alkoxy-4-oxobut-2-enylidene)phosphoranes 3.1 Synthesis 3.2 Cyclization Reactions 3.2.1 Five-Membered Rings 4 Summary