CaCl2, Bisoxazoline, and Malonate: A Protocol for an Asymmetric Michael Reaction
摘要:
A mild protocol for the asymmetric Michael addition of dimethyl malonate to various alpha,beta-unsaturated carbonyl compounds was developed. The salient feature of this methodology is that a cheap and environmentally friendly Lewis acid, CaCl2, was used as a catalyst. An aminoindanol- and pyridine-derived ligand provided in the presence of CaCl2 Michael adducts in moderate to high enantioselectivities. The scope of the reaction was demonstrated.
used as an aza-Michael donor in organocatalyticasymmetricreactions with symmetric and nonsymmetric unsaturated 1,4-diketones. After hydrolysis (in situ), the N-substituted isatins were obtained in high yields (up to >95%) with high enantioselectivity (up to 95%). Isatin was activated by derivatization to a Schiff base with aniline and used as an aza-Michael donor in organocatalyticasymmetric reactions