Fig. 2: Optimization of reaction conditions.
From: Organocatalytic enantioselective synthesis of double S-shaped quadruple helicene-like molecules
Reaction conditions: 1a (0.02 mmol, 1.0 equiv), catalyst (0.004 mmol, 20 mol%) in 2-MeTHF (1.0 mL) at corresponding temperature for 1.5 h and then N-bromo-phthalimide (NBP) (0.04 mmol, 2.0 equiv) at corresponding temperature for 2 h. Yield is that of the isolated product and enantiomeric excess (e.e.) value is determined by chiral HPLC analysis. Only one dominant diastereomer was formed under all conditions. n.d., not detected.
