Solvent-free asymmetric aminoalkylation of electron-rich aromatic compounds: Stereoselective synthesis of aminoalkylnaphthols by crystallization-induced asymmetric transformation

Electron-rich aromatic compounds such as 2-naphthol give a faster and asymm etric 1-aminoalkylation with high yields when treated with (R)-1-phenylethy lamine and aromatic aldehydes in solvent-free conditions. An asymmetric tra nsformation of a second kind, probably induced by the preferential crystall ization of one diastereomer, affords the straightforward and stereoselectiv e synthesis of aminoalkylnaphthols. Mechanisms predictable for this asymmet ric reaction are reported. The absolute configurations and the conformation s of the unknown aminonaphthols are widely ascertained.