Straightforward synthesis of alkynyl imines via 1,2-elimination of α,α-dichloroketimines

Alkylation of α,α-dichloroketimines at the α-position with benzyl bromides afforded β-arylated α,α-dichloroketimines in good yields. The latter imines could be easily transformed to the corresponding alkynyl imines, a synthetically important class of compounds, via 1,2-elimination of HCl upon treatment with 2 equiv of sodium hydride in DMSO or potassium tert-butoxide in THF.