(<i>Z</i>)-selective methoxy group-embedded Weinreb amide-type Horner–Wadsworth–Emmons reaction promoted by magnesium cation

Abstract Herein, a methoxy group-embedded Weinreb amide-type Horner–Wadsworth–Emmons reaction was developed for providing the functionally rich α,β-unsaturated carbonyl compounds. This reaction, promoted by magnesium cation, afforded the corresponding (Z)-alkenes from various substrates—including aliphatic and aromatic aldehydes—in high yields with satisfactory stereoselectivity. The elongated products, formed using the newly designed reagent, were easily converted into an α,β-unsaturated ketone, an α-keto-Weinreb amide, and further elongated compounds.