Directed Remote Lateral Metalation: Highly Substituted 2-Naphthols and BINOLs by In Situ Generation of a Directing Group.

A general synthesis of highly substituted 2-naphthols based on a new carbanionic reaction sequence is demonstrated. The reaction exploits the dual nature of lithium bases consisting of consecutive ring opening of readily available coumarins with either LiNEt2 or LiNiPr2 into Z-cinnamamides, thus generating a directing group in situ and allowing, by conformational freedom, a lateral directed remote metalation for ring closure to give the aryl 2-naphthols in good to excellent yields. These transformations can be combined to provide a more efficient one-pot process. Mechanistic insight into the remote lateral metalation step, demonstrating the requirement of Z-cinnamamide, is described. Application of this methodology to the synthesis of highly substituted 3,3'-diaryl BINOL ligands is also reported.