Thio phthalic anhydride

The decarbonylative addition of (thio)phthalic anhydrides to alkynes for the preparation of valuable (thio)isocoumarins is another application of nickel(O) catalysts for the formation of Ar-C(sp ) bonds (Scheme 22.14) [23a, b]. When the reaction is applied to thiophthalic anhydrides, benzothiophenes or thiochromanones can be prepared selectively in place of thioisocoumarins, depending on the reaction conditions employed [23h]. In related reactions, the nickel-catalyzed... 

SCHEME 22.15 Decarbonylative cycloaddition of (thio)phthalic anhydrides with allenes. 

XVII XVII, 1st Supplement (combined with Volumes XVIII and XIX) XVII, 2nd Supplement 1933 1934 1952 2359-2503 2359-3031 2359-2503 One Cyclic Oxygen (S, Se or Te). Stem nuclei Furan, 27. Thiophene, 29. Hydroxy compounds Furfuryl alcohol, 112. Carbonyl compounds Butyrolactone, 234. Furfural, 272. 2-Aeetyl-thio-phene, 287. Xanthone, 355. Succinic anhydride, 404. Phthalic anhydride, 469. 

Formation of naphthalene from phthalic anhydride and thiophene implies the extrusion of sulphur. Products arising from the reaction of this sulphur, possibly monatomic and hence highly reactive (Sidhu et al., 1966) with thiophene might be expected. Indeed, the mass spectrum revealed a product of molecular weight 116 and an isotopic distribution establishing the elemental composition as C4H4S2, doubtless thio-phenethiol. The relative amounts of the products were ... 

Fig. 25. Synthesis of polyisothianaphthene from phthalic anhydride or Fig. 28. Structure of (a) thieno[2,3-h]thiophene, (b) thieno[3,2-fc]thio-...

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