Chiral Boron Complex-Promoted Asymmetric Diels-Alder Cycloaddition and Its Application in Natural Product Synthesis

An efficient method for the asymmetric Diels-Alder cycloaddition of 2'-hydroxychalcones with acyclic or cyclic dienes has been successfully developed. The Diels-Alder cycloaddition is mediated by a chiral boron complex with VANOL, affording the corresponding products in high yields and with excellent diastereo- and enantioselectivities. This reaction enabled the enantioselective construction of cyclohexene skeletons crucial for the total synthesis of a number of Diels-Alder-type natural products (-)-nicolaioidesin C, (-)-panduratine A, (-)-kuwanon I, (+)-kuwanon J, and (-)-brosimones A and B.National High Technology Projects 973 [2015CB856200]; NNSFC [21222209, 91313303, 21472010]SCI(E)ARTICLExglei@pku.edu.cn2458-4688