The highly stereoselective addition of lithiated chloroacetylene, derived in situ from cis-1,2-dichloroethene and methyl lithium, to Ellman chiral N-tert-butanesulfinyl imines is reported. The reaction proceeds in high yield (up to 98%) and with excellent diastereoselectivity (up to >20:1) for a variety of aryl, heteroaromatic, alkyl, and α,β-unsaturated imine substrates. Transformations of the terminal chloro-substituted propargylamine products are described in which lithium-halogen exchange yields nucleophilic acetylides that can be quenched to yield terminal alkynes or intercepted by carbon electrophiles.

The reaction of chiral N‐tert‐butylsulfinyl imines (II) and (V) with in situ generated lithium chloroacetylene affords desired terminal chloro‐substituted propargylamines (III) and (VI), resp., which are converted into terminal acetylene (IV), carboxylic acid (VIII), propargylic alcohols (X), and N‐alkylated derivatives (XII).