TY - JOUR
T1 - Enantioselective Addition of Organolithium Reagents to Imines Mediated by C2-Symmetric Bis(aziridine) Ligands
AU - Johansson, F.
AU - Tanner, David Ackland
PY - 1998
Y1 - 1998
N2 - The C-2-symmetric bis(aziridine) ligands 1 - 5 have been screened in the enantioselective addition of organolithium reagents to imines. Ligand 1 (used in stoichiometric amounts) was found to be superior in terms of chemical yield and enantioselectivity, the best result being 90% yield and 89% e.e. in the addition of vinyllithium to imine 6a. Use of ligand 1 in substoichiometric amounts gave poorer yield and lower enantioselectivity. The enantioselectivity of the reaction was investigated as a function of substrate, reagent, stoichiometry and temperature, but no firm mechanistic conclusions could be drawn. Preliminary results with deuterium-labelled methyllithium indicate complexation/exchange processes involving ligand, reagent and substrate. (C) 1998 Elsevier Science Ltd. All rights reserved.
AB - The C-2-symmetric bis(aziridine) ligands 1 - 5 have been screened in the enantioselective addition of organolithium reagents to imines. Ligand 1 (used in stoichiometric amounts) was found to be superior in terms of chemical yield and enantioselectivity, the best result being 90% yield and 89% e.e. in the addition of vinyllithium to imine 6a. Use of ligand 1 in substoichiometric amounts gave poorer yield and lower enantioselectivity. The enantioselectivity of the reaction was investigated as a function of substrate, reagent, stoichiometry and temperature, but no firm mechanistic conclusions could be drawn. Preliminary results with deuterium-labelled methyllithium indicate complexation/exchange processes involving ligand, reagent and substrate. (C) 1998 Elsevier Science Ltd. All rights reserved.
U2 - 10.1016/S0040-4020(98)00675-9
DO - 10.1016/S0040-4020(98)00675-9
M3 - Journal article
SN - 0040-4020
VL - 54
SP - 11549
EP - 11566
JO - Tetrahedron
JF - Tetrahedron
IS - 38
ER -