Sequenced Reactions with Samarium(Ⅱ) Iodide. Tandem Intramolecular Nucleophilic Acyl Substitution/Intramolecular Barbier Cyclizations

摘要

Samarium(Ⅱ) iodide has been employed to promote a tandem intramolecular nucleophilic acyl substitution/ intramolecular Barbier cyclization sequence, generating bicyclic and tricyclic ring systems in excellent yield and high diastereoselectivity. Additionally, a highly versatile ring expansion—cyclization sequence allows entry into several different naturally occurring tricyclic ring systems containing seven- and eight-membered rings.