We have developed new chiral Schiff base catalysts for the enantioselective addition of diethylzinc reagents to aldehydes. The reaction of benzaldehyde with diethylzinc in the presence of 1 mol % of the chiral Schiff base catalyst proceeded to afford 1-phenyl-1-propanol in 96% enantiomeric excess (ee).
Organocatalytic Dearomative [4 + 2] Cycloadditions of Biomass-Derived 2,5-Dimethylfuran with <i>ortho</i>-Quinone Methides: Access to Multisubstituted Chromanes
The organocatalytic dearomative [4 + 2] cycloadditions of biomass-derived 2,5-dimethylfuran with ortho-quinone methides were developed, affording two different types of multisubstituted chromanes in high yields and excellent diastereoselectivities. The controllable synthesis of these two types of multisubstituted chromanes could be achieved by succinctly varying the reaction conditions.