Stereoselective reduction of ketones using extracoordinate silicon: C2-symmetric ligands

Several C2-symmetric diimidazole ligands were prepared by forming amides or imines from suitably functionalized imidazole derivatives. Extracoordinate silanes were formed by the addition of imidazolide anions to trialkoxysilanes; neutral imidazoles did not lead to observable extracoordination as judged by 29Si NMR. The extracoordinate hydrosilanes enantioselectively reduce prochiral ketones with good yield and moderate to good stereoselectivity …