Enantioselective Aza-Friedel–Crafts Reaction of Indoles and Pyrroles Catalyzed by Chiral C1-Symmetric Bis(phosphoric Acid)

• Hatano, Manabu

• Toh, Kohei

• Ishihara, Kazuaki

Bibliographic Information

Other Title

• Enantioselective Aza-Friedel–Crafts Reaction of Indoles and Pyrroles Catalyzed by Chiral <i>C</i>₁-Symmetric Bis(phosphoric Acid)

Abstract

A hydrogen bonding network in chiral Brønsted acid catalysts is important for the construction of a chiral cavity and the enhancement of catalytic activity. In this regard, we developed a highly enantioselective aza-Friedel–Crafts reaction of indoles and pyrroles with acyclic α-ketimino esters in the presence of a chiral C1-symmetric BINOL-derived bis(phosphoric acid) catalyst. The desired alkylation products with chiral quaternary carbon centers were obtained in high yields with high enantioselectivities on up to a 1.2-g scale with 0.2 mol % catalyst loading. Interestingly, the absolute configurations of the products from indoles and pyrroles were opposite even with the use of the same chiral catalyst. Moreover, preliminary mechanistic considerations disclosed that a unique hydrogen bonding network with or without π–π interactions among the catalyst and substrates might partially play a pivotal role.

Journal

• Organic Letters

  Organic Letters 22 (24), 9614-9620, 2020-12-18

  ACS Publications

Keywords

• Organic Chemistry
• Physical and Theoretical Chemistry
• Biochemistry

Details

• CRID: 1050008389814559872
• NII Article ID: 120007164856
• DOI: 10.1021/acs.orglett.0c03662
• ISSN: 15237052
• ISSN: 15237060
• HANDLE: 2237/0002001527
• Web Site: https://nagoya.repo.nii.ac.jp/records/2001527
• Web Site: https://pubs.acs.org/doi/pdf/10.1021/acs.orglett.0c03662
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN