Synthesis of Indolines via a Photocatalytic Intramolecular Reductive Cyclization Reaction
摘要:
Herein, we synthesized a series of indolines using a photocatalytic intramolecular reductive cyclization reaction. This reaction uses several N-allyl-2-iodoanilines in the presence of 10-phenylphenothiazine (Ph-PTZ) as an organic photocatalyst. Further, the corresponding aryl radical is generated through the reductive cleavage of the C I bond, generating 5-exo cyclization products.
Iridium/Brønsted acid cooperative catalyzed asymmetric allylicsubstitution reactions at the C5 position of indolines have been reported for the first time. The highly efficient protocol allows rapid access to various C5-allylated products in good to high yields (48–97%) and enantioselectivities (82% to >99% ee) with wide functional group tolerance. The transformations allow not only the formation
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
Gold-catalyzed C5-alkylation of indolines and sequential oxidative aromatization: access to C5-functionalized indoles
作者:Wenzheng Zhang、Guangyang Xu、Lin Qiu、Jiangtao Sun
DOI:10.1039/c8ob00826d
日期:——
novel protocol for the synthesis of C5-alkylated indole derivatives via a gold-catalyzed reaction of indolines with diazo compounds and subsequent oxidative aromatization has been developed. C–H bond functionalization selectively occurs at the C5-position of indolines without a directing group. The experimental operation is simple and the whole process can be manipulated in one-pot.
A facile one-pot dehydrodebenzylation of 1-benzyl-2,3-dihydroindoles to indoles uses 10% palladium on carbon as catalyst and ammonium formate as hydrogen donor in methanol.
borrowing-hydrogen methodology, this contribution describes the switch of the selectivity towards N-alkylation. Starting from indolines, N-alkylation was efficiently done using a tricarbonyl(cyclopentadienone) iron complex as the catalyst in 2,2,2-trifluoroethanol. Notably, performing the one pot N-alkylation of indolines, followed by oxidation using a FeBr3/TEMPO catalyst with t-BuOOH, the corresponding N-alkylated