Catalytic Asymmetric Chlorination of β ‐Keto Esters with Hypervalent Iodine Compounds

(Dichloroiodo)toluene (=dichloro(4‐methylphenyl)iodine; 2 ) was found to be a suitable chlorinating agent in the catalytic asymmetric chlorination of β ‐keto esters 3 catalyzed by the [Ti(TADDOLato)] complex 1 (=bis(acetonitrile)dichloro[(4 R ,5 R )‐2,2‐dimethyl‐ α , α , α ′, α ′‐tetra(naphthalen‐1‐yl)‐1,3‐dioxolane‐4,5‐dimethanolato(2−)‐ κO , κO ′]titanium), whereby α ‐chlorinated products were obtained in moderate to good yields and enantioselectivities of up to 71% ( Scheme 2, Table 2 ). The enantioselectivity of the reaction shows a remarkable temperature dependence, the maximum selectivity being obtained at ca. 50°.