Esterification of 3-hydroxy-2-naphthoic acid with homologous primary and secondary alkenyl alcohols with different chain lengths in the presence of N,N'-carbonyldiimidazole (CDI) and 1,8-diazabicyclo[ 5.4.0]undec-7-ene (DBU) in N,N-dimethylformamide gave the corresponding esters.
AbstractAn efficient chiral copper catalytic system [(R)‐(+)‐1,1′‐binaphthyl‐2,2′‐diamine‐copper(I) chloride‐TEMPO] for the asymmetric oxidative coupling of 2‐naphthol derivatives to synthesize enantiomerically enriched BINOL derivatives has been developed with good to excellent enantiomeric excess (up to 97% ee). The addition of a catalytic quantity of 2,2,6,6‐tetramethylpiperidin‐1‐yl oxyl (TEMPO) to the copper‐(R)‐(+)‐1,1′‐binaphthyl‐2,2′‐diamine complex greatly enhanced the reactivity and enantioselectivity of the enantioselective oxidative coupling of 2‐naphthol derivatives and also reduced the reaction temperature from 90 °C to room temperature in dichloromethane solvent.magnified image