1612866-69-9Relevant articles and documents
Three-component asymmetric catalytic ugi reaction - Concinnity from diversity by substrate-mediated catalyst assembly
Zhao, Wenjun,Huang, Li,Guan, Yong,Wulff, William D.
supporting information, p. 3436 - 3441 (2014/04/03)
The first chiral catalyst for the three-component Ugi reaction was identified as a result of a screen of a large set of different BOROX catalysts. The BOROX catalysts were assembled in situ from a chiral biaryl ligand, an amine, water, BH3×SMe2, and an alcohol or phenol. The catalyst screen included 13 different ligands, 12 amines, and 47 alcohols or phenols. The optimal catalyst system (LAP 8-5-47) provided α-amino amides from an aldehyde, a secondary amine, and an isonitrile with excellent asymmetric induction. The catalytically active species is proposed to be an ion pair that consists of the chiral boroxinate anion and an iminium cation. Harmonious arrangement of parts: A screen of BOROX catalysts that were generated in situ from 13 different ligands and 47 alcohols led to the identification of an effective combination for the catalytic asymmetric three-component Ugi reaction. Experimental results suggest that the catalyst is a chiral polyborate anion, which then forms an ion pair with the iminium cation that is generated from aldehyde and secondary amine.
