Elemental Sulfur‐Promoted [2+3+1] Annulation for Synthesis of Functionalized Thiochromeno[2, 3‐b]indoles from Indole Derivatives. Issue 6 (20th May 2020)

• Record Type: Journal Article
• Authors: Liu, Jianming; Wang, Zhixian; Wang, Ke; Liu, Dong; Yang, Yan; Fan, Junjun; Zhuo, Kelei; Yue, Yuanyuan
• Is Part Of: Asian journal of organic chemistry. Volume 9:Issue 6(2020)
• Page Start: 929
• Page End: 932
• Publication Date: 2020-05-20
• Subjects: [2+3+1] annulation -- C−S bond formation -- thiochromeno[2, 3-b]indoles -- elemental sulfur; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; 547.005
• DOI: 10.1002/ajoc.202000159
• Languages: English
• ISSNs: 2193-5807

Abstract

Abstract: An intermolecular [2+3+1] annulation between indole and 2‐bromobenzylaldehyde derivatives was successfully achieved by utilizing elemental sulfur as the promoter and coupling partner. This direct and operationally simple procedure provided a rapid and reliable approach to synthesize functionalized thiochromeno[2, 3‐ b ]indoles. Preliminary mechanistic studies indicated that elemental sulfur enhanced the nucleophilicity of the 3‐position of indole to attack an aldehyde group, and C−H cleavage of indole was not involved in the rate‐determining step. Abstract : An intermolecular [2+3+1] annulation between indole and 2‐bromobenzylaldehyde derivatives was successfully achieved by utilizing elemental sulfur as the promoter and coupling partner. This direct and operationally simple procedure provided a rapid and reliable approach to synthesize functionalized thiochromeno[2, 3‐ b ]indoles.