A catalyst-free approach to 3-thiocyanato-4H-chromen-4-ones

Abstract

A facile and efficient approach to 3-thiocyanato-4H-chromen-4-ones from enaminones and KSCN was realized at room temperature. In addition, one-pot synthesis of 3-thiocyanatochromenones from 2-hydroxylacetophenones was also developed.

Iodine‐Mediated Domino C(sp2)–H Sulfonylation/Annulation of Enaminones and Sulfonyl Hydrazines for the Synthesis of 3‐Sulfonyl Chromones

“…Zhou and co‐workers developed a direct chromone C–H sulfenylation reaction for the synthesis of 3‐sulfenyl chromones (Scheme b), and our group also recently realized the synthesis of 3‐sulfenyl chromones by enaminone cyclization and C–H sulfonylation under the catalysis of KIO 3 (Scheme b) . In addition, the synthesis of 3‐thiocyano chromones through a key C–H thiocyanation step was also reported (Scheme c) . Interestingly, although the sulfonyl group is a privileged sulfur‐containing group, the synthesis of sulfonyl chromones by C–H‐coupling‐based sulfonylation remains unsuccessful.…”

Sustainable Synthetic Approaches Involving Thiocyanation and Sulfur- Cyanation: An Update

“…In this section, the domino reactions will be described in which the introduction of the thiocyanate function is accompanied by a subsequent carbo-or hetero-cyclization, leading to thiocyanated heterocyclic compounds. Various enaminones (65) were reacted with KSCN in the presence of K 2 S 2 O 8 , at room temperature, and led to 3thiocyanatochromenones (66) via a domino underwent thiocyanation/cyclization process in good yields (Scheme 27) [28]. The authors also developed a one-pot version of the method starting from 2-hydroxyl acetophenones.…”

C3‐Functionalized Chromones Synthesis by Tandem C−H Elaboration and Chromone Annulation of Enaminones

“…Accordingly, the synthesis of 3‐thiocyanochromones also received high concerns. Chen and Yu et al . developed the method for 2‐thiocyanochromones synthesis by means of the K 2 S 2 O 8 ‐triggered reactions of enaminones 1 and KSCN ( 49 ).…”