Enantioselective Michael addition reactions of malononitrile catalyzed by chiral Lewis acid and achiral amine catalysts
摘要:
Reactions of malononitrile with 3-(2-alkenoyl)-2-oxazolidinones or 1-(2-alkenoyl)-4-bromo-3,5-dimethylpyrazoles can be doubly activated by the use of catalytic amounts (10 mol% each) of both, (R,R)-DBFOX/Ph-Ni(ClO4)(2)(.)3H(2)O and amines, to give the Michael adducts in high chemical yields with satisfactory enantioselectivities. (C) 2003 Elsevier Science Ltd. All rights reserved.
Double catalytic enantioselective Michael addition reactions of tertiary nucleophile precursors—tertiary/quaternary and quaternary/quaternary carbon–carbon bond formations
Enantioselective Michael addition reactions of tertiary nucleophile precursors, such as substituted malononitriles and cyclic 1,3-diketones, can be successfully activated by the metal complexes derived from R,R-DBFOX/Ph chiral ligand and cationic metal salts. With this method, the enantioselective tertiary/quaternary and quaternary/quaternary carbon–carbon bond formations can be achieved. Use of alcohol