title: Using chiral ionic liquid additives to enhance asymmetric induction in a Diels-Alder reaction.
abstract: A bis-oxazoline ligand has been complexed using Cu(ii) and Zn(ii) trifluoromethanesulfonate and a range of chiral ionic liquid (CIL) additives based on natural products were used as a co-catalyst for a Diels-Alder reaction. The catalytic performance of these systems was compared for the asymmetric Diels-Alder reaction between N-acryloyloxazolidinone and cyclopentadiene with and without the presence of a CIL additive. In the absence of the CIL, both catalysts resulted in low enantioselectivities in conventional solvents and ionic liquids. However, whilst only a minor effect of the CIL was observed for the Cu based catalyst, in the case of the Zn based catalyst, significant enhancements in endo enantioselectivity of up to 50% were found on the addition of a CIL.
authors.affiliation: School of Chemistry and Chemical Engineering/QUILL, Queen's University, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, UK. p.goodrich@qub.ac.uk m.j.muldoon@qub.ac.uk.
authors.forename: P
authors.initials: P
authors.lastname: Goodrich
authors.affiliation: School of Chemistry and Chemical Engineering/QUILL, Queen's University, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, UK. p.goodrich@qub.ac.uk m.j.muldoon@qub.ac.uk.
authors.forename: H Q
authors.initials: HQ
authors.lastname: Nimal Gunaratne
authors.affiliation: School of Chemistry and Chemical Engineering/QUILL, Queen's University, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, UK. p.goodrich@qub.ac.uk m.j.muldoon@qub.ac.uk.
authors.forename: L
authors.initials: L
authors.lastname: Hall
authors.affiliation: School of Chemistry and Chemical Engineering/QUILL, Queen's University, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, UK. p.goodrich@qub.ac.uk m.j.muldoon@qub.ac.uk.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Science, China Pharmaceutical University, Nanjing, 210009, P. R. China.
authors.forename: L
authors.initials: L
authors.lastname: Jin
authors.affiliation: School of Chemistry and Chemical Engineering/QUILL, Queen's University, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, UK. p.goodrich@qub.ac.uk m.j.muldoon@qub.ac.uk.
authors.forename: M J
authors.identifier: http://orcid.org/0000-0002-9286-9672
authors.initials: MJ
authors.lastname: Muldoon
authors.affiliation: Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: A P C
authors.initials: AP
authors.lastname: Ribeiro
authors.affiliation: Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: A J L
authors.initials: AJ
authors.lastname: Pombeiro
authors.affiliation: University of Bucharest, Department of Chemical Technology and Catalysis, B-dul Regina Elisabeta 4-12, Bucharest 030016, Romania.
authors.forename: V I
authors.initials: VI
authors.lastname: Pârvulescu
authors.affiliation: Givaudan, Schweiz AG, Überlandstrasse 138, CH-8600 Dübendorf, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Davey
authors.affiliation: School of Chemistry and Chemical Engineering/QUILL, Queen's University, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, UK. p.goodrich@qub.ac.uk m.j.muldoon@qub.ac.uk and School of Chemical Engineering and Analytical Science, The University of Manchester, Sackville Street, Manchester, M13 9PL, UK. c.hardacre@manchester.ac.uk.
authors.forename: C
authors.identifier: http://orcid.org/0000-0001-7256-6765
authors.initials: C
authors.lastname: Hardacre