Asymmetric synthesis of N-allylic indoles via regio- and enantioselective allylation of aryl hydrazines
نویسندگان
چکیده
The asymmetric synthesis of N-allylic indoles is important for natural product synthesis and pharmaceutical research. The regio- and enantioselective N-allylation of indoles is a true challenge due to the favourable C3-allylation. We develop here a new strategy to the asymmetric synthesis of N-allylic indoles via rhodium-catalysed N-selective coupling of aryl hydrazines with allenes followed by Fischer indolization. The exclusive N-selectivities and good to excellent enantioselectivities are achieved applying a rhodium(I)/DTBM-Segphos or rhodium(I)/DTBM-Binap catalyst. This method permits the practical synthesis of valuable chiral N-allylated indoles, and avoids the N- or C-selectivity issue.
منابع مشابه
Ligand-enabled Ir-catalyzed intermolecular diastereoselective and enantioselective allylic alkylation of 3-substituted indoles.
An Ir-catalyzed asymmetric allylic alkylation of 3-substituted indoles is reported. The reaction provides indoline products containing multiple contiguous stereocenters with high site-, regio-, diastereo- and enantioselectivities in one step from a wide range of readily available starting materials. The key to this method is the high level of diastereocontrol enabled by an iridium catalyst deri...
متن کاملEnantioselective construction of C-chiral allylic sulfilimines via the iridium-catalyzed allylic amination with S,S-diphenylsulfilimine: asymmetric synthesis of primary allylic amines.
We have devised a highly regio- and enantioselective iridium-catalyzed allylic amination reaction with the sulfur-stabilized aza-ylide, S,S-diphenylsulfilimine. This process provides a robust and scalable method for the construction of aryl-, alkyl- and alkenyl-substituted C-chiral allylic sulfilimines, which are important functional groups for organic synthesis. Additionally, the combination o...
متن کاملAsymmetric Synthesis of Borylalkanes via Copper-Catalyzed Enantioselective Hydroallylation.
An efficient synthetic method for preparing enantioenriched secondary borylalkanes has been achieved through a copper-catalyzed regio- and enantioselective hydroallylation of alkenyl boronates and boramides employing hydrosilanes and allylic phosphates. In the presence of a copper catalyst with a chiral Walphos ligand, a range of alkenylboron compounds with an aryl, heteroaryl, or alkyl substit...
متن کاملThree-component procedure for the synthesis of new chiral spirooxindolopyrrolizidines via catalytic highly enantioselective 1,3-dipolar cycloaddition
The catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reaction of azomethine ylides, derived from isatin, with electron-deficient dipolarophilewas described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imine)–Cu(...
متن کاملThree-Component Procedure for the Synthesis Chiral Spirooxindolopyrrolizidines via Catalytic Highly Enantioselective 1,3-Dipolar Cycloaddition of Azomethineylides and 3-(2-Alkenoyl)-1,3-Oxazolidin-2-ones
The catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reactionof azomethineylides, derived from isatin, with electron-deficient dipolarophilewas described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imi...
متن کامل