Stereoselective reactions. 15.1 total synthesis of (+)-ivalin by utilizing asymmetric double alkylation reaction of α,β-unsaturated aldimine

Abstract An asymmetric total synthesis of (+)-ivalin ( 4 ), a representative of antileukemic eudesmane sesquiterpenes, is described. The ene-aldehyde ( 6 ) was converted to the nearly optically pure alcohol ( 20 ) through the asymmetric double a1ky1ation reaction of the chiral ene-enamine ( 14 ). The ene-carbonyl cyclization of ( 25 ) with tin(IV) chloride afforded the core skeleton ( 26 ). The stereoinversion of hydroxyl group and further transformation furnished (+)-ivalin ( 4 ).