Switchable Palladium-Catalyst Reaction of Bromomethyl Sulfoxides, CO, and N-Nucleophiles: Aminocarbonylation at Csp3 versus Oxidative Carbonylation of Amines

The palladium-catalyzed reaction of alpha-bromomethyl sulfoxides, carbon monoxide, and N-nucleophiles follows different reaction pathways according to the catalytic system and the reaction conditions. The Pd-xantphos catalyst affords high yields of alpha-sulfinyl amides by an aminocarbonylation process and is the first example of this type of transformation for a nonbenzylic sp(3)-hybridized carbon. On the other hand, the oxidative carbonylation of amines occurs with alpha-bromomethyl sulfoxides, carbon monoxide, and catalytic Pd(PPh3)(4) under aerobic conditions, yielding ureas and oxalamides from either primary or secondary amines. The reaction with ambident nucleophiles such as amino alcohols was highly selective and took place exclusively at the amino group despite the presence of the alcohol functionality. In parallel to the reaction paths for simple amines, amino alcohols were converted into hydroxy sulfinyl amides when the reaction was catalyzed by Pd-xantphos, while Pd(PPh3)(4) catalyst afforded cyclic carbamates. The alkoxycarbonylation reaction of bromomethyl sulfoxides with simple alcohols and CO leading to the corresponding sulfinyl esters is also described.