REACTIONS OF TOSYL AZIDE WITH 2-PHENOXYSULFANYL2,3-DIHYDRO-1H-INDANE-1,3-DIONE AND 2-PHENYLSULFANYL2,3-DIHYDRO-1H-INDANE-1,3-DIONE - UNEXPECTED REACTIVITY OF INTERMEDIATE 4-ACYL-5-HYDROXY-1-TOSYLTRIAZOLINES

The reaction of tosyl azide 1 with 2-phenoxy-2;3-dihydro-1H-indane-1,3-dione 2c, carried out in hexamethylphosphoramide (HMPA) or in diethyl ether in the presence of triethylamine, fails to afford the expected diazo transfer product, i. e. the diazoacetophenone 3c (3c'), but instead leads to the dimeric indanedione 7 the formation of which is primarily ascribable to preferential fragmentation of the transient hydroxytriazoline 4c to give zwitterion 9c and dinitrogen. Under comparable conditions, tosyl azide 1 and 2-phenylsulfanyl-2,3-dihydro-1H-indane-1,3-dione 2d in HMPA gives the ring-expanded hydroxybenzopyran 15, the formation of which is similarly ascribed to preferential fragmentation of the corresponding 4,5-dihydro-1H-triazole 4d to give zwitterion 9d. However, analogous reaction of the dione 2d in THF, in the presence of triethylamine, affords 2-diazo-2,3-dihydro-1H-indane-1,3-dione along with diphenyl disulfide, toluene-p-sulfonamide and phenyl toluene-4-thiosulfonate. These latter-products are believed to arise from ready decomposition of the 4,5-dihydro-1 H-triazole 4d precursor, i.e the triazenyl anion 13. X-Ray crystal structure analyses of compound 7 and the acetoxybenzopyran 17 are also reported.