Highly Stereoselective Syntheses of All 1,2,3-Me,OH,Me Triads via Asymmetric Hydrogenation Reactions

Iridium-catalyzed asymmetric hydrogenations of chiral alkenes were used to access four pivotal a,?-functionalized chirons, that contain widely occurring stereochemical 1,2,3-Me,OH,Me motifs. A chiral analogue of Crabtrees catalyst was used in key hydrogenation steps to form these motifs with high stereochemical purities. An application of one of these chirons is illustrated here with a synthesis of (-)-invictolide.