Polycyclic [2+3]-Cycloadducts from the Thermal Decomposition of Bis(2,5-dihydro-1,3,4-thiadiazoles) in the Presence of N-Methylmaleimide

Thermal decomposition of a mixture of the two stereoisomeric bis(2,5-dihydro-1,3,4-thiadiazoles) cisand trans-2, which was prepared by treatment of 2,2,4,4-tetramethylcyclobutane-1,3-dithione with excess of diazomethane in the presence of two equivalents of N-methylmaleimide, led to a mixture of three 1:2 cycloadducts of type 4. The structures of these thiocarbonyl methanide-adducts have been established by X-ray crystallography. In the presence of only one equivalent of N-methylmaleimide, a complex mixture of the three 1:2 adducts of type 4, the known dispirocyclic bis-thiiranes cisand trans-3, and a 1:1 adduct 6, containing one thiirane ring and one fragment resulting from a [2+3]-cycloaddition of a thiocarbonyl methanide, was formed. The structure of the latter has again been proven by X-ray crystallography. Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-80005 Accepted Version Originally published at: Mloston, Grzegorz; Celeda, Malgorzata; Linden, Anthony; Heimgartner, Heinz (2004). Polycyclic [2+3]Cycloadducts from the Thermal Decomposition of Bis(2,5-dihydro-1,3,4-thiadiazoles) in the Presence of N-Methylmaleimide. Polish Journal of Chemistry, 78(11-12):2089-2099.