Nickel-Catalyzed Enantio- and Regioconvergent Synthesis of Allyl Aryl Thioethers from α- or γ-Silylated Allylic Chlorides

An enantio- and regioconvergent allylic substitution of non-symmetrical 1,3-disubstituted allylic chlorides with thiophenols under nickel catalysis is reported. The use of 18-crown-6 as an additive is crucial for obtaining good yields. Despite competing uncatalyzed nucleophilic displacement as a background reaction as well as undesirable sulfur–nickel interactions, the method enables access to enantioenriched allylic thioethers with generally good regioselectivity. Modest to good enantioselectivities were obtained for different allylic electrophiles as well as thiophenols. The present investigation expands the use of phenols to thiophenols as nucleophilic partners and highlights its limitations. This work is an example of an elusive enantioconvergent nickel-catalyzed allylic substitution with sulfur nucleophiles, especially employing less established non-symmetrical 1,3-disubstituted allyl electrophiles