Application of 7‐Indolylmethanols in Catalytic Asymmetric Arylations with Tryptamines: Enantioselective Synthesis of 7‐indolylmethanes

Abstract

The application of 7‐indolylmethanols in catalytic asymmetric reactions has been established via an enantioselective arylation reaction with tryptamines in the presence of chiral phosphoric acid, which afforded a series of structurally diversified chiral 7‐indolylmethanes in moderate to good yields and generally excellent enantioselectivities (23 examples, up to 92% ee). This reaction not only provides a useful strategy for the enantioselective synthesis of chiral 7‐indolylmethanes, but also represents a good example of 7‐indolylmethanol‐involved catalytic asymmetric reaction, which will greatly enrich the chemistry of indolylmethanols.magnified image

Chiral Phosphoric Acid Catalyzed Asymmetric Synthesis of Hetero‐triarylmethanes from Racemic Indolyl Alcohols

“…Moreover, The MeO and NH groups in the 7‐indolylmethanols contribute to stabilizing either the 6‐methide‐6 H ‐indoles or carbocation species and could be beneficial for stereoselectivity . Having noticed the unique reactivity of the designed 7‐indolylmethanol, we expect that this strategy could be further applied to the remote stereoinduction …”

Advances in The Catalytic Synthesis of Triarylmethanes (TRAMs)

“…The reaction is believed to advance through a cascade catalytic dehydration to generate the 6‐methide‐6H‐indoles intermediate followed by an unusual 1,8‐nucleophilic addition to furnish the desired triarylmethane 114 and 116 . This method provides an opportunity to create structurally diversified indolyl‐substituted triarylmethanes with substituents at the remote C7 position, …”

Organocatalytic Enantioselective Synthesis of Chiral Allenes: Remote Asymmetric 1,8‐Addition of Indole Imine Methides

“…[8] Various asymmetric reaction modes of indole-based imine methides have been documented, [8] especially on cycloaddition [9] and either 1,4-or 1,6-conjugate addition. [10] However, among these examples, limited success was achieved for remote asymmetric addition (e.g., 1,8-addition), which is undoubtedly an inherent challenge because of issues like regioselectivity and stereocontrol. [6h, 11] In this context, beautiful work by Antilla and co-workers on the enantioselective arylation of 6-indolylmethanols is worthy of note.…”