Stereoelectronic Model To Explain Highly Stereoselective Reactions of Seven‐Membered‐Ring Oxocarbenium‐Ion Intermediates

Abstract Nucleophilic attack on seven‐membered‐ring oxocarbenium ions is generally highly stereoselective. The preferred mode of nucleophilic attack forms the product in a conformation that minimizes transannular interactions, thus leading to different stereoselectivity as compared to that of reactions involving six‐membered‐ring oxocarbenium ions.