Alkyne–thiocarbonyl metathesis instead of Diels–Alder addition: Coupling of thiopyrano[4, 3-b]indole-3(5H)-thiones and dimethyl acetylenedicarboxylate. (23rd April 2022)

• Record Type: Journal Article
• Authors: Suzdalev, Konstantin F.; Vyalyh, Julia V.; Tkachev, Valery V.; Burov, Oleg N.; Lisovin, Anton V.; Kletskii, Mikhail E.; Borodkin, Gennady S.; Kurbatov, Sergey V.; Lysenko, Ekaterina A.
• Is Part Of: Tetrahedron. Volume 112(2022)
• Publication Date: 2022-04-23
• Subjects: Metathesis -- Rearrangement -- DMAD -- 2H-thiopyran-2-thione -- Thiophene -- Cycloaddition; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2022.132751
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The cascade reaction of thiopyrano[4, 3- b ]indole-3(5 H )-thiones and dimethyl acetylenedicarboxylate (DMAD) was found. The mechanism has been investigated in detail by DFT PCM/B3LYP/6–311++G(d, p) quantum chemical calculations. Initially, the reaction occurs via an alkyne–thiocarbonyl metathesis mechanism. At the next stages, unprecedented rearrangement takes place: thiopyrane ring opening and thiophene ring closure proceed. Cycloaddition of intermediate thioketone and a second equivalent of DMAD leads to the resulting thiopyrano[4, 3- b ]indole derivative bearing thienyl substituent. Graphical abstract: Image 1