Tandem Cyclization Reaction between Optically Active γ-Nitro Ketone and Chalcone towards the Synthesis of Chiral Cyclohexane Skeletons Bearing Five Stereocenters

Chiral cyclohexane motif is widespread in the molecular structures of nature products and medicinal chemicals. And polysubstituted chiral cyclohexanes are important building blocks in organic synthesis. A tandem cyclization via asymmetric induction for the construction of polysubstituted chiral cyclohexane skeletons is described. In the presence of phase-transfer-catalyst, optically active gamma-nitro ketone reacted with chalcone smoothly to afford cyclohexane skeletons bearing five consecutive stereocenters in 40%similar to 71% yields with 90%similar to 98% ee. It should be noted that the scope of chalcone is broad. Especially, the asymmetric induction is kept at a high level in each step of the tandem cyclization reaction.