Fig. 6. Preparative synthesis and transformations.
a Gram-scale synthesis of (rac)-QUINOL and (rac)-QUINAP. b Synthesis of (R)-QUINAP from (R)-QUINOL N-oxide. Reaction conditions: i Tf2O (1.05 eq.), DMAP (2.0 eq.), CH2Cl2, r.t., 10 h; ii diphenylphosphine oxide (2.0 eq.), Pd(OAc)2 (12 mol%), L1 (24 mol%), DIPEA (5.5 eq.), DMSO, 110 °C, 24 h; iii bis(pinacolato)diboron (1.0 eq.), diglyme, 70 °C, 12 h; iv HSiCl3 (10.0 eq.), DIPEA (40.0 eq.), toluene, 70 °C, 4 h.