Asymmetric synthesis with cinchona-decorated cyclodextrin in a continuous-flow membrane reactor

Peter Kisszekelyi, Abdulaziz Alammar, Jozsef Kupai*, Peter Huszthy, Julia Barabas, Tibor Holtzl, Lajos Szente, Carlo Bawn, Ralph Adams, Gyorgy Szekely

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

This work presents a cyclodextrin-enhanced organocatalytic method from molecular to process design. Cinchona-thiourea and -squaramide catalysts were covalently anchored to inherently large, stable and well-defined permethyl-β-cyclodextrins. The asymmetric catalysis was successfully demonstrated on the Michael reaction of 1,3-diketones and trans-β-nitrostyrene. Both emerging green and conventional solvents were screened for the asymmetric addition (up to 99% ee), and the Kamlet–Taft solvent parameters were correlated to the enantioselectivity. Quantum chemical modelling revealed that the catalyst anchoring resulted in favorable structural changes, and stronger intermolecular interactions between the catalyst and the reagents. Continuous organocatalysis was performed in coiled tube flow reactor coupled with a membrane separation unit, which allowed complete recovery of the catalyst and 50% solvent (2-MeTHF) recycling. The 100% conversion, 98% purity, 99% ee, 100% in-line catalyst recovery, and 80 g L−1 h−1 productivity makes it an attractive catalytic platform.

Original languageEnglish (US)
Pages (from-to)255-261
Number of pages7
JournalJournal of Catalysis
Volume371
DOIs
StatePublished - Mar 2019

Keywords

  • CNXCXSMYMLPAMS-UHFFFAOYSA-N
  • Catalyst recovery
  • Continuous processes
  • FHPSEPBVFKHFNY-UHFFFAOYSA-N
  • Flow chemistry
  • GANRWJWDBLKUJA-UHFFFAOYSA-N
  • HBOZSVVDCDBTLC-UHFFFAOYSA-N
  • HGVZOZLENNRYCV-FEBSWUBLSA-N
  • In-line recycling
  • NRTGMGHTTXZAHK-FEQNNBRFSA-N
  • Organic solvent nanofiltration
  • Organocatalysis
  • PKIQKQBPSHXGJH-PBFVBANWSA-N
  • URYLJCBFCXEADB-UHFFFAOYSA-N
  • USUKGXSBXPEYAE-UHFFFAOYSA-N
  • VXCPMTROKJXPOD-AVOXONOSSA-N

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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