Rhodium-Catalyzed Enantioselective Intramolecular Hydroalkoxylation of Allenes and Application in the Total Synthesis of (R,R,R)-α-Tocopherol.

We report herein of a novel, enantioselective and rhodium- catalyzed cyclisation of allenyl alcohols towards chiral α-vinylic, cyclic ethers employing a rhodium/(R,R)-Me-ferrocelane catalyst. The corresponding chiral cyclic products were obtained in general high yields and enantioselectivities. The synthetic value of our obtained products was further exemplified by transformations of the allylic ether function.

Iridium-Catalyzed Enantioselective and Diastereoselective Hydrogenation of 1,3-Disubstituted Isoquinolines.

The development of a general method utilizing a hydroxymethyl directing group for asymmetric hydrogenation of 1,3-disubstituted isoquinolines to provide chiral 1,2,3,4-tetrahydroisoquinolines is reported. The reaction, which utilizes [Ir(cod)Cl] and a commercially available chiral xyliphos ligand, proceeds in good yield with high levels of enantioselectivity and diastereo-selectivity (up to 95% ee and >20:1 dr) on a range of differentially substituted isoquinolines. Directing group studies demonstrate that the hydroxymethyl functional group at the C1-position is more efficient at enabling hydrogenation than other substituents, although high levels of enantioselectivity were conserved across a variety of polar and non-polar functional groups.