Chiral Bisoxazoline Metal Complexes On The 1,3-Dipolar Cycloaddition Reaction Of Nitrone

In recent years, chiral bis(oxazolines)ligands with a various of structural diversity have received a great deal of attention through their efficiently use in numerous asymmetric reactions, including 1,3-dipolar cycloaddition reaction, cyclopropanation, Diels-Alder, allylic substitution and Michael addition reactions. Chiral bis(oxazolines)ligands with a various of structural diversity have been prepared from malonate, tartrate, pyridine, biphenyl, binaphthalene, biferrocene and other derivatives. There are two typical motheds preparing chiral bis(oxazolines)lig-ands:the one is contemporary synthesizing the double oxazolines, using the dicarboxylic acid diverdity acyl chloride and esters reacted with chiral aminoalcohol to obtain diamide alcohol, then it was cyclyzated after activated by Bu2SnCl, (i-PrO)4Ti, SOCl, TsCl, MsCl, BF3.OEt, DAST, Burgess reagent, the other is for chiral bis(oxazolines)ligands which have been prepared from binaphthalene and biferrocene via synthesizing the single oxazolines at first, then obtained the box ligands at the catalyztion of the catalyzer.This paper is throw light on the catalytic effect of the complexes of Copper(II) or Zinc(II) with chiral bis(oxazoline) on the cycloaddition reactions of C,N-diphenylnitrone 130 with 3-((E)-2-Butenoyl)-1,3-oxazolin-2-one 128 or 2,3-dihydrofuran 129. The research results show that different metal and dipolephile perform a different effect on the cycloaddition reactions of nitrone, which result in the acceleration of reaction rate and the change of reaction stereoselectivity.The reaction rate of 139 with 140 was more rapidnessly than the reaction 128 with 130, catalyzed by the catalyst or without.To the effect of the metal in the reaction rate, the complex of Copper(II)...