Asymmetric hydrogenation approaches to valuable, acyclic 1,3-hydroxymethyl chirons.

An iridium carbene oxazoline complex was used to catalyze hydrogenations of trisubstituted alkenes to give terminal and internal 1,3-hydroxymethyl chirons. The products are accessible in all possible stereoisomeric forms. These hydrogenations do not require strongly coordinating functionalities on the substrate, and in some key cases, catalyst- rather than substrate-controlled stereoselectivities are observed. It is hypothesized that these reactions would not be feasible using iridium or rhodium diphosphine complexes.