Zinc Radical Transfer Based Modular Approach to Enantiopure Alkylidene‐β‐prol­ines from N‐(tert‐Butylsulfinyl)‐α‐(aminomethyl)acrylates

N-(tert-Butylsulfinyl)-α-(aminomethyl)acrylates with tethered silylated alkynes undergo a tandem 1,4-addition/carbozincation reaction upon exposure to dialkylzinc compounds in the presence of air. The process follows a zinc-radical-transfer mechanism and provides vinylzinc adducts that can react subsequently with electrophiles. High levels of chiral induction (dr > 90:10) from the tert-butylsulfinyl directing group are achieved during the radical 5-exo-dig cyclization by adding samarium(III) triflate. The sequence overall provides straightforward modular access to enantiopure (E)-4-alkylidene-β-prolines from tert-butanesulfinamide.