Application of Asymmetric Catalysis in the E/Z-Stereodivergent Synthesis of Alkenes

Catalytic asymmetric reactions are primarily used to install new stereogenic centers highly enriched in either the R or the S configuration. Here, we demonstrate that chiral catalysts can also be used to control the E/Z geometry of an alkene product devoid of chirality. The process is akin to a parallel kinetic resolution in the sense that a chiral catalyst converts two enantiomers of a starting material to two different products, in this case, only differing in the E/Z geometry of an alkene. The reaction is a reductive addition of a 1,1-dichloroalkene to a chiral secondary allylic alcohol. The catalyst controls the facial selectivity of addition to the allylic alcohol, and a subsequent anti-selective β-hydroxide elimination dictates the E/Z geometry of the alkene product. Synthetic applications of the skipped 1,4-diene products and studies probing the origin of stereoselectivity are described.