Catalytic Enantioselective Total Synthesis of Riccardiphenol B

• DOI: 10.1002/adsc.201500928
• Publication Date: 2016-01-21T13:19:10Z
• Authors: Pierre Cottet; Christian Bleschke; Montse Guiteras C...; Matthieu Tissot; Alexandre Alexakis
• Keywords: info:eu-repo/classification/ddc/540; Total synthesis; 01 natural sciences; Quaternary stereocenters; 0104 chemical sciences; Michael addition; ddc:540; Asymmetric catalysis; Enolate trapping; Riccardiphenol B; Sesquiterpenes

AbstractThe first catalytic enantioselective total synthesis of riccardiphenol B, a sesquiterpene derivative isolated from a Japanese collection of the liverwort Riccardia crassa, has been achieved. A copper‐catalyzed asymmetric conjugate addition of trimethylaluminum was used at an early stage to generate the quaternary stereogenic center with high enantiomeric excess. The corresponding sterically encumbered aluminum enolate was directly trapped with an α‐amino ether, allowing after oxidation, the release of a key intermediate in the total synthesis of the target natural product.magnified image