| Autor: |
Poulsen PH; Department of Chemistry, Aarhus University , DK-8000 Aarhus C, Denmark., Vergura S; Department of Chemistry, Aarhus University , DK-8000 Aarhus C, Denmark., Monleón A; Department of Chemistry, Aarhus University , DK-8000 Aarhus C, Denmark., Jørgensen DK; Department of Chemistry, Aarhus University , DK-8000 Aarhus C, Denmark., Jørgensen KA; Department of Chemistry, Aarhus University , DK-8000 Aarhus C, Denmark. |
| Abstrakt: |
The regio- and stereoselective control of cycloaddition reactions to polyconjugated systems has been demonstrated by applying asymmetric organocatalysis. Reaction of 2,4-dienals with nitrones allows for a highly regio- and stereoselective 1,3-dipolar cycloaddition in the presence of an aminocatalyst. The first cycloaddition on the remote olefin can be followed either by a cascade reaction or by other selective reactions of the remaining olefin. The chiral products are obtained in good to high yields and excellent diastereo- and enantioselectivities. The remote selective concept has been extended to 2,4,6-trienals by means of a novel enantioselective triple cascade 1,3-dipolar cycloaddition reaction. The formation of chiral poly 1,3-amino alcohols is also demonstrated. |
