Continuous flow preparation of enantiomerically pure BINOL(s) by acylative kinetic resolution
Abstract
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 mmolprod ⋅ mmolcat−1 ⋅ h−1.
Citation
Lai , J , Neyyappadath , R M , Smith , A D & Pericàs , M A 2020 , ' Continuous flow preparation of enantiomerically pure BINOL(s) by acylative kinetic resolution ' , Advanced Synthesis & Catalysis , vol. Early View . https://doi.org/10.1002/adsc.201901420
Publication
Advanced Synthesis & Catalysis
Status
Peer reviewed
ISSN
1615-4150Type
Journal article
Description
Financial support from CERCA Programme/Generalitat de Catalunya, MINECO (CTQ2015-69136-R) and AGAUR/Generalitat de Catalunya (2017 SGR 1139) is gratefully acknowledged.Collections
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