Synthesis, resolution and rates of racemisation of 1-(2′-methyl-3′-indenyl)-2-naphthylamine and -2-naphthol

Axially chiral ligands 1-(2′-methyl-3′-indenyl)-2-naphthylamine 7 and -2-naphthol 8 have been prepared in three and four steps, respectively, from 2-nitro-1-naphthol. Following resolution by chiral HPLC, the absolute configurations were assigned by circular dichroism as (aR)-(−)-7 and (aR)-(+)-8. The enantiomers of both ligands have significant thermal stability, with half-lives for racemisation of 73 h at 144°C and 220 h at 110°C, for 7 and 8, respectively.