Fluxionally Chiral DMAP Catalysts: Kinetic Resolution of Axially Chiral Biaryl Compounds

Abstract

Can organocatalysts that incorporate fluxional groups provide enhanced selectivity in asymmetric transformations? To address this issue, we have designed chiral 4-dimethylaminopyridine (DMAP) catalysts with fluxional chirality. These catalysts were found to be efficient in promoting the acylative kinetic resolution of secondary alcohols and axially chiral biaryl compounds with selectivity factors of up to 37 and 51, respectively.

Understanding the Reactivity and Selectivity of Fluxional Chiral DMAP‐Catalyzed Kinetic Resolutions of Axially Chiral Biaryls

“…In continuation of our efforts to understand the stereoselectivity of organocatalyzed reactions, particularly in the context of KRs, we have examined the KR of axially chiral biaryls reported by Sibi and co‐workers in 2014 (Scheme ) . In this reaction, chiral DMAP catalyst A serves as a highly selective catalyst when paired with isobutyric anhydride as the acylating agent.…”

Practical and Scalable Kinetic Resolution of BINOLs Mediated by a Chiral Counterion

“…[8] An alternative approach from the Sibi group ( Figure 1B) involves employing ac hiral 4-dimethylaminopyridine equivalent to enable enantioselective O-acylation of am onofunctionalized BINOL derivative with s up to 38. [9] Arelated acylative approach from Zhao ( Figure 1C)e mploys an Nheterocyclic carbene in the presence of an a-alkoxyaldehyde.…”

Catalytic Kinetic Resolution of Biaryl Compounds

“…A novel chiral 4‐(dimethylamino)pyridine (DMAP)‐catalyzed acylative kinetic resolution of axially chiral biaryl derivatives was reported by Sibi and co‐workers (Scheme ) 45. Both the recovered axially chiral biaryl substrates and the acylated product were obtained with good to high enantioselectivities.…”