Enantioselective total synthesis of (+)-conicol via cascade three-component organocatalysis.

The first asymmetric total synthesis of (+)-conicol has been achieved via a key step reaction involving the organocatalytic domino oxa-Michael-Michael-Michael-aldol condensation of 2-((E)-2-nitrovinyl)benzene-1,4-diol and alpha,beta-unsaturated aldehydes. Structures of the three-component domino reaction adducts, 20 and 21, including their absolute configurations, were confirmed unambiguously by X-ray analysis. Through this work, the absolute configuration of (+)-conicol was thereby elucidated.