scheme3

Scheme 3. Scope of arylboronic acids and aryldiazonium salts^a. ^aUnless otherwise noted, the reaction was conducted with 2a(0.2 mmol),3 (0.2 mmol), 4 (0.1 mmol), Rb₂CO₃ (0.3 mmol), (R)-1a (0.012 mmol) and Pd₂dba₃ (0.004 mmol) in MTBE (2 mL) at 0 ºC for 48 h under Ar. Isolated yields are shown. The er values were determined by SFC. ^bEt₂O was used instead of MTBE as the solvent. ^cGuanidine carbonate was used instead of Rb₂CO₃. ^dGuanidine carbonate (1.0 equiv) and Rb₂CO₃ (1.0 equiv) were used instead.