An efficient, asymmetric, catalytic, triple-cascade reaction between α-keto esters
and nitroalkenes to construct cyclohexanes with six vicinal stereogenic centers in
good yields and with high enantioselectivities has been established. A bifunctional
guanidine–amide organocatalyst proved to be useful for the Michael/Michael/Henry sequence
through Brønsted base and hydrogen-bonding cooperative catalysis.
Key words
asymmetric catalysis - cascade reaction - cyclohexanes - organocatalysis - keto esters
- nitroalkenes