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Kinetic and Dynamic Kinetic Resolution of Racemic Tertiary Bromides by Pentanidium‐Catalyzed Phase‐Transfer Azidation
Author(s) -
Ren Jingyun,
Ban Xu,
Zhang Xin,
Tan Siu Min,
Lee Richmond,
Tan ChoonHong
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202000138
Subject(s) - kinetic resolution , kinetic energy , phase (matter) , catalysis , chemistry , materials science , thermodynamics , organic chemistry , enantioselective synthesis , physics , classical mechanics
We have developed a method to afford enantiomerically enriched tertiary azides and bromides through pentanidium‐catalyzed kinetic resolution (KR) of racemic tertiary bromides under base‐free conditions. We found that the absence of water is crucial to attain a high selectivity factor ( s ). On the other hand, new experimental observations and DFT modeling led us to propose that enantioconvergent azidation of tertiary bromides proceeded through dynamic kinetic resolution (DKR). The investigations particularly identified the crucial roles of base and water in the enantioconvergent process, thus supporting the proposal that the tertiary bromide isomerizes in the presence of base and water through a S N 2X pathway.