Thioketones reaction with diazoalkanes

Another synthetic route to episulfides is by reaction of a diazoalkane (18) with either sulfur or a thioketone (19) (Scheme 13). 

A (1/7-imidazol-l-yl) silver species (55) has been postulated as the key intermediate in the 3-l-2-cycloaddition reaction of diazoalkanes (54) with benzynes yielding 2-aryl-2H-indazoles (56) (Scheme 18). The 3-I-2-cycloaddition reaction of 3-trifluoromethyl-4-diazopyrazolinones with dialkyl acetylene dicarboxylates, in refluxing toluene, produced spiro 3/f-pyrazole adducts that rearranged to the trifluoromethyl-substituted pyrazolo[l,5-fi(][l,2,4]triazin-7-ones. ° The 1,3-dipolar cycloaddition reaction of aromatic thioketones (58) with 2-aza-1,3-dicarbonyl compounds (57), at 20-50 C, yielded thiadiazoline adducts (59) that readily eliminate nitrogen to produce oxathioles (60) in moderate yields (up to 70%) (Scheme 19). ... 

The reactions of thioketones, thiono-esters, and dithio-esters with diazoalkanes yield thiirans (6) and often the olefinic product (7) formed by... 

Many papers have reported on the reaction of thioketones with diazoalkanes." " " " ITie normal products are thiirans or/and substituted vinyl alkyl sulphides, depending on the ability of the thione to exist in... 

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