Reaction of o-bromoaryl- and o-bromoarylalkyl phthalimides with n-butyllithium at low temperatures

Abstract

The work of Parham, Jones and Sayed,1 which demonstrates that bromine-lithium exchange, occurs in preference to carbonyl addition in aromatic amide derivatives of o-bromo-β-phenylpropionic acid, led to the consideration of using o-bromoaryl phthalimides 1a-c as precursors for the preparation of multi-ring nitrogen heterocycles and for elaborations of aromatic systems requiring an amine-protecting group (Figure 1). While the chemistry of the addition of Grignard and organolithium reagents to phthalimides is well known,2 to the best of our knowledge, attempts to carry out the addition of the these reagents to brominated phthalimide derivatives such as 1a-c have not been studied.