amine-salicylamide derived from chiral trans-cyclohexane-1,2-diamine was used as an organocatalyst for the enantioselective conjugate addition of aldehydes, mainly α,α-disubstituted to N-substituted maleimides. The reaction was performed in toluene as a solvent at room temperature. The corresponding enantioenriched adducts were obtained with high yields and enantioselectivities up to 94%. Theoretical calculations
Organocatalytic enantioselective conjugate addition of aldehydes to maleimides in deep eutectic solvents
作者:Jesús Flores-Ferrándiz、Rafael Chinchilla
DOI:10.1016/j.tetasy.2016.12.009
日期:2017.2
The conjugate enantioselective addition of aldehydes, mainly alpha,alpha-disubstituted, to maleimides leading to enantioenriched succinimides, has been achieved in recyclable deep eutectic solvents at room temperature. Enantiomerically pure carbamate-monoprotected trans-cyclohexane-1,2-diamines are used as organocatalysts, affording high yields and up to 94% ee of the final succinimides. The product can be extracted from the deep eutectic solvent, which retains the chiral organocatalyst, allowing both the solvent and catalyst to be reused. (C) 2016 Elsevier Ltd. All rights reserved.
Solvent-dependent enantioswitching in the Michael addition of α,α-disubstituted aldehydes to maleimides organocatalyzed by mono-N-Boc-protected cyclohexa-1,2-diamines