Stereoselective Synthesis of (<i>E</i>)‑3-Alkylideneoxindoles <i>via</i> Gold(I)-Catalyzed Cross-Coupling of 3‑Diazooxindoles with Diazoesters

A versatile gold­(I)-catalyzed cross-coupling reaction of 3-diazooxindoles with diazoesters has been presented, affording (E)-3-alkylideneoxindoles stereoselectively. Density functional theory calculations rationalized the chemo- and stereoselectivity of the reaction, which was in good agreement with experimental observations. In addition, (E)-3-alkylideneoxindoles were converted into their (Z)-isomers under UV-irradiation facilely, indicating the great advantage of this approach in stereoselective synthesis of both (E)- and (Z)-3-alkylideneoxindoles.