Intramolecular Addition of a Dimethylamino C(sp3)–H Bond across C–C Triple Bonds Using IrCl(DTBM-SEGPHOS)(ethylene) Catalyst: Synthesis of Indoles from 2-Alkynyl-N-methylanilines
Intramolecular addition of a C(sp3)–H bond of the dimethylamino group across the C–C triple bond in 2-alkynyl-N,N-dimethylanilines is effectively catalyzed by a new iridium complex, IrCl(DTBM-SEGPHOS)(C2H4), in mesitylene at 150 °C. The intramolecular C(sp3)–H addition is followed by double-bond isomerization to afford 3-substituted indoles in good to high yields.
Asymmetric Cycloisomerization of <i>o</i>
-Alkenyl-<i>N</i>
-Methylanilines to Indolines by Iridium-Catalyzed C(sp<sup>3</sup>
)−H Addition to Carbon-Carbon Double Bonds
diphosphine effectively promotes the intramolecular addition of the C(sp3)−H bond across a carbon–carbon double bond in a highly enantioselective fashion. The reaction gives indolines bearing a quaternary stereogenic carbon center at the 3‐position. The reactionmechanism involves rate‐determining oxidative addition of the N‐methyl C−H bond, followed by intramolecular carboiridation and subsequent reductive