Palladium-Catalyzed Stille-Type Coupling of <i>N</i>‑Acyl Iminium Ions with Distannanes: A Multicomponent Synthesis of α‑Amidostannanes

2015-12-17T00:56:09Z (GMT) by Boran Xu Bruce A. Arndtsen
The palladium-catalyzed three-component coupling of imines, acid chlorides, and hexabutyldistannane is described. This results in the synthesis of various α-amidostannanes in good yields, without the use of strong nucleophilic organometallic reagents. The reaction is believed to proceed via a Stille-type cross coupling of an <i>in situ</i>-generated <i>N</i>-acyl iminium salt with Bu<sub>3</sub>SnSnBu<sub>3</sub> and reaches completion within 1 h at ambient temperature using simple, unligated Pd<sub>2</sub>dba<sub>3</sub> as a catalyst. Combining the formation of α-amidostannanes with lithiation and carboxylation allows the overall synthesis of amino acid derivatives in two steps from imines, acid chlorides, and CO<sub>2</sub>.