Synthesis of tetrahydroisoquinoline (TIQ)-oxazoline ligands and their application in enantioselective Henry reactions
2010 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 7, 846-852 p.Article in journal (Refereed) Published
A novel family of eleven new tetrahydroisoquinoline (TIQ)-oxazoline intermediates and five corresponding copper(II) catalysts has been developed and applied to the catalytic asymmetric Henry reaction of various aldehydes with nitromethane to provide beta-hydroxy nitroalkanes in high conversion (>99%) This paper describes the synthesis of the TIQ compounds from L-dihydroxyphenylalanine (L-DOPA) as the starting material The chiral ligands were complexed in situ with various transition metals such as Cu, Sc, Co, Zn, Ni and Mn and tested as a chiral catalyst for the Henry reaction The reaction was optimized in terms of the metal, counter ion, solvent, temperature and over a range of substrates The corresponding catalyst with copper(II) acetate and 2-propanol as the solvent provides the best enantioselectivities (up to 77% ee) of the corresponding nitroalcohol for 4-chlorobenzaldehyde.
Place, publisher, year, edition, pages
2010. Vol. 21, no 7, 846-852 p.
IdentifiersURN: urn:nbn:se:uu:diva-136005DOI: 10.1016/j.tetasy.2010.04.053ISI: 000279493400014OAI: oai:DiVA.org:uu-136005DiVA: diva2:376283