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Continuous Flow Preparation of Enantiomerically Pure BINOL(s) by Acylative Kinetic Resolution
Author(s) -
Lai Junshan,
Neyyappadath Rifahath M.,
Smith Andrew D.,
Pericàs Miquel A.
Publication year - 2020
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201901420
Subject(s) - chemistry , kinetic resolution , selectivity , dichloromethane , catalysis , enantioselective synthesis , simulated moving bed , flow chemistry , polystyrene , resolution (logic) , yield (engineering) , chromatography , adsorption , organic chemistry , thermodynamics , polymer , artificial intelligence , physics , solvent , computer science
A polystyrene‐immobilized isothiourea has been applied to the enantioselective acylative kinetic resolution (KR) of monoacylated BINOL(s) with inexpensive isobutyric anhydride in batch and flow. High selectivity values ( s =29 at 0 °C) and a remarkable stability of the catalytic system in the operation conditions have been recorded for unsubstituted BINOL. No significant loss of activity/selectivity is recorded after 10 consecutive KR cycles in batch. A continuous flow process has been implemented and operated with a 100 mmol (32.8 g) sample of racemic monoacetylated BINOL in dichloromethane solution in an 84 hours experiment with a packed bed reactor containing 1 g ( f =0.37 mmol.g −1 ) of the functional resin ( s =17–21). Residence time can be decreased to 10 min with the same reactor to achieve a conversion of 58% with a selectivity factor s =17 when a more highly functionalized catalyst ( f =0.88 mmol.g −1 ) is used. This translates into a remarkable combined productivity of 5.5 mmol prod ⋅ mmol cat −1 ⋅ h −1 .