A copper-catalyzed arylation of tryptamines for the direct synthesis of aryl pyrroloindolines

An operationally simple, copper-catalyzed arylation of N-tosyltryptamines provides direct access to C3-aryl pyrroloindolines. A range of electron-donating and electron-withdrawing substituents is tolerated on both the indole backbone and the aryl electrophile. These reactions occur under ambient temperatures and with equimolar quantities of the coupling partners

A Mild and General Larock Indolization Protocol for the Preparation of Unnatural Tryptophans

A mild and general protocol for the Pd(0)-catalyzed heteroannulation of o-bromoanilines and alkynes is described. Application of a Pd(0)/P(^tBu)_3 catalyst system enables the efficient coupling of o-bromoanilines at 60 °C, mitigating deleterious side reactions and enabling access to a broad range of useful unnatural tryptophans. The utility of this new protocol is demonstrated in the highly convergent total synthesis of the bisindole natural product (−)-aspergilazine A

Enantioselective Synthesis of Tryptophan Derivatives by a Tandem Friedel–Crafts Conjugate Addition/Asymmetric Protonation Reaction

The tandem Friedel–Crafts conjugate addition/asymmetric protonation reaction between 2-substituted indoles and methyl 2-acetamidoacrylate is reported. The reaction is catalyzed by (R)-3,3′-dibromo-BINOL in the presence of stoichiometric SnCl_4, and is the first example of a tandem conjugate addition/asymmetric protonation reaction using a BINOL·SnCl_4 complex as the catalyst. A range of indoles furnished synthetic tryptophan derivatives in good yields and high levels of enantioselectivity, even on a preparative scale. The convergent nature of this transformation should lend itself to the preparation of unnatural tryptophan derivatives for use in a broad array of synthetic and biological applications

Copper-Catalyzed Diastereoselective Arylation of Tryptophan Derivatives: Total Synthesis of (+)-Naseseazines A and B

A copper-catalyzed arylation of tryptophan derivatives is reported. The reaction proceeds with high site- and diastereoselectivity to provide aryl pyrroloindoline products in one step from simple starting materials. The utility of this transformation is highlighted in the five-step syntheses of the natural products (+)-naseseazine A and B

Copper-Catalyzed Diastereoselective Arylation of Tryptophan Derivatives: Total Synthesis of (+)-Naseseazines A and B

A copper-catalyzed arylation of tryptophan derivatives is reported. The reaction proceeds with high site- and diastereoselectivity to provide aryl pyrroloindoline products in one step from simple starting materials. The utility of this transformation is highlighted in the five-step syntheses of the natural products (+)-naseseazine A and B

Enantioselective Synthesis of Tryptophan Derivatives by a Tandem Friedel–Crafts Conjugate Addition/Asymmetric Protonation Reaction

The tandem Friedel–Crafts conjugate addition/asymmetric protonation reaction between 2-substituted indoles and methyl 2-acetamidoacrylate is reported. The reaction is catalyzed by (<i>R</i>)-3,3′-dibromo-BINOL in the presence of stoichiometric SnCl₄, and is the first example of a tandem conjugate addition/asymmetric protonation reaction using a BINOL·SnCl₄ complex as the catalyst. A range of indoles furnished synthetic tryptophan derivatives in good yields and high levels of enantioselectivity, even on a preparative scale. The convergent nature of this transformation should lend itself to the preparation of unnatural tryptophan derivatives for use in a broad array of synthetic and biological applications

Copper-Catalyzed Diastereoselective Arylation of Tryptophan Derivatives: Total Synthesis of (+)-Naseseazines A and B

A copper-catalyzed arylation of tryptophan derivatives is reported. The reaction proceeds with high site- and diastereoselectivity to provide aryl pyrroloindoline products in one step from simple starting materials. The utility of this transformation is highlighted in the five-step syntheses of the natural products (+)-naseseazine A and B

Enantioselective Synthesis of Tryptophan Derivatives by a Tandem Friedel–Crafts Conjugate Addition/Asymmetric Protonation Reaction

The tandem Friedel–Crafts conjugate addition/asymmetric protonation reaction between 2-substituted indoles and methyl 2-acetamidoacrylate is reported. The reaction is catalyzed by (<i>R</i>)-3,3′-dibromo-BINOL in the presence of stoichiometric SnCl₄, and is the first example of a tandem conjugate addition/asymmetric protonation reaction using a BINOL·SnCl₄ complex as the catalyst. A range of indoles furnished synthetic tryptophan derivatives in good yields and high levels of enantioselectivity, even on a preparative scale. The convergent nature of this transformation should lend itself to the preparation of unnatural tryptophan derivatives for use in a broad array of synthetic and biological applications