abstract
A chiral bis(oxazoline) bearing CH2OH groups was synthesized from a commercial bis(oxazoline) and characterized by H-1- and C-13-NMR, high resolution ESI-mass spectrometry and FTIR. The corresponding copper(II) complex was immobilized onto the surface of a mesoporous carbonaceous material (Starbon (R) 700) in which the double bonds had been activated via conventional bromination. The materials were characterized by elemental analysis, ICP-OES, XPS, thermogravimetry and nitrogen adsorption at 77 K. The new copper(II) bis(oxazoline) was tested both in the homogeneous phase and once immobilized onto a carbonaceous support for the kinetic resolution of hydrobenzoin. Both were active, enantioselective and selective in the mono-benzoylation of hydrobenzoin, but better enantioselectivities were obtained in the homogeneous phase. The heterogeneous catalyst could be separated from the reaction media at the end of the reaction and reused in another catalytic cycle, but with loss of product yield and enantioselectivity.
keywords
HETEROGENEOUS CATALYSTS; ACTIVATED CARBON; ENANTIOSELECTIVE CATALYSIS; ASYMMETRIC BENZOYLATION; MESOPOROUS SILICAS; CYCLOPROPANATION; EPOXIDATION; AZA-BIS(OXAZOLINE); MICROWAVE; REPLICAS
subject category
Chemistry
authors
Carneiro, L; Silva, AR; Shuttleworth, PS; Budarin, V; Clark, JH
our authors
Ana Rosa Silva
Principal Researcher
Liliana Patrícia Teixeira Carneiro
Research FellowshipGroups
Projects
acknowledgements
This work was funded by Fundacao para a Ciencia e a Tecnologia (FCT) through the project PTDC/QUI/64770/2006, which was co-financed by EU under the programs COMPETE, QREN and FEDER, and performed under the COST Action TD1203. ARS thanks FCT, FSE and POPH for the contract under the program Investigator FCT 2012 (IF/1300/2012), as well as for financing under the program Pest-C/CTM/LA0011/2013 (CICECO). PS gratefully acknowledges the Ministerio de Ciencia e Innovacion for the concession of a Juan de la Cierva (JCI-2011-10836) contract.