In this third installment of the "Stereoselective Heterocyclic Synthesis" series, there are four reviews that provide the scientific community with recent developments in stereoselective synthesis and the use of various heterocyclic compounds. The majority of the chapters deal with nitrogen-containing heterocycles, beginning with a survey of intramolecular 1,3-dipolar cycloaddition of N,O dipoles, with attention paid to the stereochemical issues of the cycloaddition. Chapter 2 provides a summary of the synthesis and utility of 4-substituted-1,3dioxanes, whereas the next chapter details the synthesis and utility of aziridines and three-membered ring aza-heterocycles. Recent strategies developed for the synthesis of medium-sized lactam ring systems are discussed in the final chapter.Chapter 1, "Stereoselective Intramolecular 1,3-Dipolar Cycloaddition" by Namboothiri and Hassner, provides an extensive review of intramolecular cycloaddition reactions involving nitrile oxides, silyl nitronates, oximes, azides, and nitrilimines. The authors provide synthetic examples of substrates (e.g., pyrrolidines from intramolecular oxime-olefin cycloadditions) that can be formed by each of the previous reaction types. The utility of these important reactions is detailed in the chapter, although the references in general appear somewhat dated. This chapter gives references for the preparation as well as the reaction of each dipolar species and provides numerous synthetic examples.Sinz and Rychnovsky wrote the second chapter, entitled "4-Acetoxy-and 4-Cyano-1,3-dioxanes in Synthesis", which discusses the background, preparation, and reactions of the title compounds. In addition, the authors have included examples of a variety of lithio-derived synthons prepared from either the thiophenyl-or tributylstannyl-substituted dioxanes. The authors utilize their extensive experience with substituted dioxanes to discuss the application of these important 1,3-diol synthons to the synthesis of both syn-and anti-polyol-containing natural products. In each section, the authors provide numerous, documented examples with well-illustrated schemes, reaction conditions, and reagents.In the third chapter, "The Synthetic Potential of Three-Membered Ring Aza-Heterocycles", Zwanenburg and ten Holte begin with a short introduction about the preparation of aziridine and azirine intermediates and then spend the majority of the review discussing the utility and pertinent reactions applied to three-membered heterocycles. The authors pay particular attention to the utility of aziridine-2-carboxylic esters. Reactions of aziridines and azirines include ring expansion, amino acid and alcohol synthesis, application as chiral ligands, and their use as reactive synthons. The authors supply the reader with up-todate references that cover much of the recent literature, including a number of synthetic schemes.In the final chapter, "Synthesis of Medium-Sized Ring Lactams", Nubbemeyer reviews four general methods designed to prepare lactam rings. The review covers ring-cl...