Reactions of alpha-diazocycloalkanones with thiocarbonyl compounds

Reactions of 2-diazocyclohexanone (7) with thioketones and a 1,3-thiazoie-5 (4H)-thione in THF at 50-60 degrees C in the presence of 10% LiClO4 proceed ed by elimination of N-2 and yielded 4,5,6,7-tetrahydro-1,3-benzoxathiole d erivatives (13-17). In the case of 2,2,4,4-tetramethylcyclobutane-1,3-dithi one (12), a 1:5 mixture of cis- and trans-bisadducts (cis/trans-17) was obt ained. Under analogous conditions, no reactions occurred with 5,5-dimethyl- 2-diazocyclohexane-1,3-dione (18). Only in the presence of 2% Rh-2(OAc)(4), 18 reacted with dithione (12) yielding the 1,3-benzoxathiole derivative (1 9).