Improving enantioselectivity via rationally tuning electronic effects of catalysts in the organocatalytic asymmetric aldol reaction

Both steric repulsion and electronic effect govern the stereoselectivity in asymmetric catalysis. Rationally electronic-tuned N-(2-hydroxylphenyl)-(S)- prolinamide derived catalysts were designed, synthesized, and evaluated in the asymmetric aldol reaction. The results indicate that the enantiomeric ratios of products correlate well with the Hammett constants, which confirms that the enantioselectivity was improved via rationally tuning catalyst electronic effects.