Chemo- and regioselective [3 + 2]-cycloadditions of thiocarbonyl ylides: crystal structures of trans-8-benzoyl-1,1,3,3-tetramethyl-7-trifluoromethyl-5-thiaspiro[3.4]octan-2-one and trans-3-benzoyl-2,2-diphenyl-4-(trifluoromethyl)tetrahydrothiophene

Abstract

The title compounds were prepared via chemo- and regioselective [3 + 2]-cyclo­additions. The thio­phene ring in each crystal structure has an envelope conformation. The largest differences between the two mol­ecular structures is in the bond lengths about the quaternary C atom of the thio­phene ring. In the spiro­cyclic structure, the C—C bonds to the spiro C atom in the cyclo­butane ring are around 1.60 Å and weak inter­molecular C—H⋯X (X = S, O) inter­actions link the mol­ecules into extended ribbons. In the other structure, weak C—H⋯π inter­actions link the mol­ecules into sheets.