1240163-27-2Relevant academic research and scientific papers
Synthesis of tetrahydroisoquinoline (TIQ)-oxazoline ligands and their application in enantioselective Henry reactions
Kawthekar, Rahul B.,Chakka, Sai Kumar,Francis, Vivian,Andersson, Pher G.,Kruger, Hendrik G.,Maguire, Glenn E. M.,Govender, Thavendran
experimental part, p. 846 - 852 (2010/11/02)
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 β-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.
