Generation of (E)-silylketene acetals in a Rhodium-DuPhos catalyzed two-step reductive aldol reaction.

[reaction: see text]. Mechanistic studies employing in situ NMR analysis implicate intermediate silicon enolates as reactive intermediates in the Rh-DuPhos catalyzed two-step reductive aldol reaction with Cl(2)MeSiH. These enolates undergo noncatalyzed reaction with a variety of aldehydes to give the derived syn-aldol adduct in high yields and diastereoselection.

Enantio- and diastereoselective reductive aldol reactions with iridium-pybox catalysts.

[see reaction]. A catalytic amount of [(cod)IrCl]2 and indane-pybox converts diethylmethylsilane, methyl acrylate, and certain aldehydes to the derived reductive aldol adduct with good enantio- and diastereocontrol.