L‐Proline‐Catalyzed One‐Pot Diastereoselective Synthesis of Cyclohexanols from β‐Aryl‐γ‐nitroketones and α,β‐Unsaturated Aldehydes: A New Route to 2,3,4,6‐Tetrasubstituted Phenols

A wide array of densely functionalized cyclohexanol derivatives having five contiguous chiral centers were efficiently achieved in good to high yields with high diastereoselectivities. The double C−C bonds forming reaction proceeds via a domino nitro‐Michael/aldol reaction between several β‐aryl‐substituted‐γ‐nitroketones and a range of β‐aryl‐substituted acroleins as Michael acceptors catalyzed by L‐proline as a naturally available, non‐toxic, cheap organocatalyst. Several important features of this strategy include 100% atom‐economical, high‐efficiency, operational simplicity, and broad functional‐group tolerance. Gratifyingly, one‐pot conversion of cyclohexanols to a novel class of 2,3,4,6‐tetrasubstituted phenols under metal‐free conditions has been demonstrated.