Pd-Catalyzed Synthesis of Ar-SCF3 Compounds under Mild Conditions-

Reaction Scheme


We report the first example of a coupling reaction of chiral secondary boronic esters generated by the hydroboration of vinyl arenes. In order for the reaction to take place in high yields, the use of silver oxide as a base and the presence of at least 8 equiv of triphenyl phosphine per Pd are required. The reaction proceeds with >90% retention of configuration in all cases except one. Remarkably, the linear boronate ester does not react under these conditions



Under inert atmosphere, 4-iodoacetophenone (24.6 mg, 0.100 mmol) (R)-1a (34.1 mg, 0.147 mmol) Ag2O (35.4 mg, 0.152 mmol), Pd2(dba)3 (3.69 mg, 0.0040 mmol, 8.1 mol% Pd), PPh3 (26.0 mg, 0.099 mmol) were taken up in THF (1.9 g). The reaction was sealed, and stirred at 70 �C for 24 h. The desired product was isolated by column chromatography (gradient 20:1 to 10:1 hexanes: ethyl acetate). Enantiomeric ratio was determined by SFC analysis (AD-H Column, 5% MeOH, 2 mL, 200 bar) to be 85:15, a 93% retention of er



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