Azabis(oxazolines) prove to be superior ligands for the enantioselective, cobalt(II)-catalyzed conjugate reduction of α,β-unsaturated carbonyl compounds with sodium borohydride. β-Trisubstituted α,β-unsaturated esters and amides as well as γ-butenolides are readily converted to their corresponding saturated counterparts with enantioselectivities up to 97% ee.
氮杂双(
恶唑啉)被证明是对映选择性,
钴(II)催化的
硼氢化钠对α,β-不饱和羰基化合物的共轭还原反应的优良
配体。β-三取代的α,β-不饱和酯和酰胺以及γ-
丁烯内酯很容易转化为相应的饱和对映体,对映选择性高达97%ee。