TITLE:
Rhodium Catalyzed [2π + 2π + 2π]-Cycloaddition of Alkynyl-Ynamides and Carbon Disulfide to Indolo-Thiopyrane Thiones
AUTHORS:
Benjamin Dassonneville, Felix Hinkel, Heiner Detert
KEYWORDS:
Cycloaddition, Heterocycles, Rhodium, Sulfur, Alkyne
JOURNAL NAME:
International Journal of Organic Chemistry,
Vol.13 No.1,
March
14,
2023
ABSTRACT: The synthesis of new indoloannulated thiopyranethiones is reported. The key-step is a rhodium-catalyzed [2 + 2 + 2]-cycloaddition of alkynyl-ynamides with carbon disulfide to close the pyrrole and the thiopyranethione rings simultaneously. A violet idolothiopyrane thione or a mixture of the violet and a red isomer result from [RhCl(C8H14)2]2/3BINAP catalyzed cycloadditions, the regiochemistry is controlled by the substitution pattern on the alkynyl-ynamide.