Atropisomeric diastereoisomers from nucleophilic attack on 8-acyl-1-naphthamides

Restricted rotation about the Ar-CO bond means that 1-naphthamides bearing chiral 8-substituents may exist as pairs of diastereoisomeric atropisomers. These atropisomers are formed with good to excellent stereoselectivity for the syn-diastereoisomer by the reaction of 8-formyl-1-naphthamides with or ganolithiums and Grignard reagents. The reduction of 8-acyl-1-naphthamides also proceeds with syn-selectivity. The product alcohols are prone to lacto nisation and also to epimerisation, and some of the apparent diastereoselec tivities may be the result of thermodynamic, rather than kinetic, control.