Phosphoric Acid Catalyzed Electrophilic Thiocyanation of Indoles: Access to SCN‐Containing Aryl‐Indole Compounds

Abstract

A phosphoric acid catalyzed electrophilic thiocyanation of 3‐aryl indoles, which provides an efficient and modular approach to SCN‐containing 3‐aryl indole compounds, was developed for the first time. A variety of 2‐SCN‐3‐aryl indoles were obtained with moderate to excellent yields. Furthermore, catalytic asymmetric manner of this reaction was also studied. Using chiral phosphoric acid as the catalyst, axially chiral SCN‐containing 3‐aryl indoles were obtained in moderate to good yields with moderate enantioselectivity.

Catalytic Synthesis of Atropoisomers via Non‐Canonical Friedel‐Crafts Reactions

“…However, only moderate enantioselectivity was achieved. [120] Scheme 34. Chiral sulfide-catalyzed Enantioselective carbothiolation for construction of axially chiral amino sulfides.…”

“…In addition to the aforementioned works, Chen's team also reported an antroposelective electrophilic thiocyanation of indole compounds with N ‐thiocyanatosaccharin for construction of axially chiral SCN‐containing 3‐aryl indoles via kinetic resolution approach. However, only moderate enantioselectivity was achieved [120] …”