Unexpected enhancement of enantioselectivity in copper(II) catalyzed conjugate addition of diethylzinc to cyclic enones with novel TADDOL phosphorus amidite ligands
Unexpected enhancement of enantioselectivity in copper(II) catalyzed conjugate addition of diethylzinc to cyclic enones with novel TADDOL phosphorus amidite ligands
Samenvatting
The copper(II) catalyzed enantioselective 1,4-addition reactions of diethylzinc to cyclic enones in the presence of novel phosphorus amidite ligands, easily prepared from α,α,α',α'-tetraphenyl-2,2'-dimethyl-1,3- dioxolane-4,5-dimethanol (TADDOL) derivatives, resulted in e.e.s up to 71% for cyclohexenone and up to 62% for cyclopentenone. A remarkable enhancement of enantioselectivity was observed upon the addition of powdered molecular sieves to the reaction mixture.
Organisatie | Hanze |
Gepubliceerd in | Tetrahedron: asymmetry Elsevier, Vol. 9, Uitgave: 14, Pagina's: 2409-2413 |
Datum | 1998-07-17 |
Type | Artikel |
DOI | 10.1016/S0957-4166(98)00240-7 |
Taal | Engels |