Formation of optically active chromanes by catalytic asymmetric tandem oxa-Michael addition-Friedel-Crafts alkylation reactions.
A novel tandem reaction involving an oxa-Michael addition, followed by a Friedel-Crafts alkylation has been developed. This catalytic tandem reaction, which provides facile and efficient access to optically active functionalised chromanes, proceeds under the influence of bisoxazoline-based catalysts to give diastereomerically pure products in enantioselectivities up to 81% and excellent yields. The optimisation studies, the scope of the reaction, and a model that on the basis of PM3 calculations predicts the outcome of the reaction will be detailed.
van Lingen
Hester L
HL
Danish National Research Foundation, Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
Zhuang
Wei
W
Hansen
Tore
T
Rutjes
Floris P J T
FP
Jørgensen
Karl Anker
KA