Inversion or Retention? Effects of Acidic Additives on the Stereochemical Course in Enantiospecific Suzuki-Miyaura Coupling of α-(Acetylamino)benzylboronic Esters

摘要

The stereochemical course of the stereo-specific Suzuki-Miyaura coupling of enantioenriched a-(acetylamino)benzylboronic esters with aryl bromides can be switched by the choice of acidic additives in the presence of a Pd/XPhos catalyst system. Highly enantiospecific, invertive C-C bond formation takes place with the use of phenol as an additive. In contrast, high enantiospecificity for retention of configuration is attained in the presence of Zr(Oi-Pr)_4-i-PrOH as an additive.