Steric effects in the synthesis of ortho-substituted 1,1'-binaphthalene derivatives by the SRN1 and the Stille reaction

The scope of the S RN 1 mechanism and the Stille reaction to synthesize 1,1´-binaphthalene derivatives was investigated.The best yield of 2'-methoxy-1,1'-binaphthalenyl-2-ol (52%) was obtained in liquid ammonia or DMSO by the S RN 1 irradiated reaction of 1-iodo-2methoxynaphthalene with the anion of 2-naphthol.A lower yield (40%) of BINOL is obtained in water with 1-iodo-2-hydroxynaphthalene as substrate when the reaction is sonicated before irradiation.The Stille reaction between (2-methoxy-1-naphthyl)-trimethylstannane and 1-iodo-2methoxynaphthalene afforded low yields (15-11%) of the 1,1´-binaphthalene derivative.Based on AM1 and B3LYP calculations the yields of the 1,1´-binaphthalene derivatives obtained through the electron transfer S RN 1 reaction can be attributed to kinetic factors of the radicalnucleophile coupling step.