Triple Cascade Reaction Leading to Tetra-Substituted Cyclohexenes

Significance

A novel 3-component organocatalytic cascade reaction is reported that generates cyclohexene derivatives 5 with four contiguous stereogenic centers in good diastereoselectivities (from 2.1:1 to 99:1) and high enantioselectivities (>99%). A large variety of substrates can be used: aldehyde 2 can be aliphatic or highly functionalized; the α,β-unsaturated aldehyde 4 tolerates aromatics as well as aliphatics. However, nitro­olefin 3 is limited to aromatic substrates. Surprisingly, the product itself did not react further with the catalyst, possibly due to steric hindrance.