Diastereomerically or enantiomerically selective lactonisation

Abstract

A method of forming a $g(g)-lactone said method characterized by reacting together a symmetrical or a non-symmetrical 1,2-dioxine of the formula (1), wherein R?1¿ and R?2¿ are the same or different and are groups in which a carbon atom is bonded to the dioxine backbone; and a doubly stabilised ester nucleophile. The nucleophile is a stabilized enolate nucleophile generated from reaction of an ester, ketone or nitrile in the presence of a base. Conducting the reaction in the presence of a cobalt catalyst a chiral ligand results in a $g(g)-lactone.