Atroposelective attack of nucleophiles on 2-formyl-1-naphthamides and their derivatives: Chelation and non-chelation control

Organometallic nucleophiles attack 2-formyl-l-naphthamides to give secondary alcohols with widely varying atroposelectivity. By careful choice of reagent, selectivities of up to >99:1 in favour of either the anti or the syn atropisomer can be obtained. Ethers and amines may be synthesised atroposelectively from acetals or imines. The sense of the selectivity is determined by the reactive conformation of the Ar-CHO bond, itself dependent on the coordinating and chelating ability of the nucleophile's counterion. The roles of conformation, Lewis acids, and chelation/non-chelation control in relation to stereoselectivity are discussed.