185981-08-2Relevant academic research and scientific papers
Free-Radical Ring Expansion by one Carbon Atom by Decomposition of the Thiohydroxamic Esters of (1-Alkoxycarbonyl-2-oxocycloalkyl)acetic Acids
Matovic, Radomir,Cekovic, Zivorad
, p. 483 - 488 (2007/10/03)
A free-radical ring expansion by one carbon atom has been achieved by thermal decomposition of thiohydroxamic esters of (1-alkoxycarbonyl-2-oxocycloalkyl)acetic acids, 8.Thus, by decomposition of thiohydroxamic esters 8a-f in boiling toluene, ethyl 3-oxocycloalkenecarboxylates 9a-f are obtained as principal ring-enlarged products in 27-58percent yield; accompanied by ethyl 1-(4-methyl-2-thiazolylthio)-3-oxocycloalkane-1-carboxylates 10c,d (24percent yield) with the ring expanded by one carbon atom.Unrearranged ethyl 1-(4-methyl-2-thiazolylthiomethyl)-2-oxocycloalkane-1-carboxylates) 11a-f are formed as side products (8-17percent yield).Ring expansion involves the following sequence of reactions: 3-exo-cyclization (to C=O grup), cleavage of the cyclopropane ring, intermolecular addition to the thione group of thiohydroxamic esters and elimination reaction.
