Vinylogous Organocatalytic Triple Cascade Reaction: Forging Six Stereocenters in Complex Spiro-Oxindolic Cyclohexanes
作者:Indranil Chatterjee、David Bastida、Paolo Melchiorre
DOI:10.1002/adsc.201300667
日期:2013.11.11
AbstractWe report a triple vinylogous cascade reaction, yielding valuable spiro‐oxindolic cyclohexane derivatives. The three‐component domino process proceeds by way of a catalyzed Michael/1,6‐addition/vinylogous aldol sequence affording the products with six stereogenic centers and very high control over the stereochemistry. The chemistry is based on a rare example of asymmetric 1,6‐addition to linear 2,4‐dienals proceeding with complete δ‐site selectivity. Key to the reaction development was a directing group positioned at the β‐dienal position, which was essential for achieving highly predictable reaction outcomes.magnified image