Nitro-Enabled Atroposelective Dynamic Kinetic Resolution of 2-Arylindoles by Phase-Transfer Catalysis
Chanhee Lee1, Sujin Lee1, Ahreum Kim1
1School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Abstract:
This study presents the atroposelective alkylation of 2-arylindoles catalyzed by a substituted cinchonium salt as a phase-transfer catalyst. Under the optimized reaction conditions, various substrates are employed to yield products with high enantioselectivity. The presence of an ortho-nitro group at the aromatic ring is essential for high atroposelectivity, because it facilitates favorable interactions between the catalyst and substrate. The origin of the enantioselectivity reveals favorable π-π interactions for both enantiomers and unfavorable steric strains for undesired enantiomers.
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