Inversion or retention? Effects of acidic additives on the stereochemical course in enantiospecific Suzuki-Miyaura coupling of α-(acetylamino)benzylboronic esters

Tomotsugu Awano; Toshimichi Ohmura; Michinori Suginome

doi:10.1021/ja210025q

Inversion or retention? Effects of acidic additives on the stereochemical course in enantiospecific Suzuki-Miyaura coupling of α-(acetylamino)benzylboronic esters

J Am Chem Soc. 2011 Dec 28;133(51):20738-41. doi: 10.1021/ja210025q. Epub 2011 Dec 5.

Authors

Tomotsugu Awano¹, Toshimichi Ohmura, Michinori Suginome

Affiliation

¹ Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan.

PMID: 22129167
DOI: 10.1021/ja210025q

Abstract

The stereochemical course of the stereospecific Suzuki-Miyaura coupling of enantioenriched α-(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.