C-Sulfonylhydrazones

A variation on the thermal reactions of diazo compounds with alkenes is the decomposition of salts of sulfonylhydrazones. This procedure, known as the BamfoTd-Stevens reaction, is believed to occur via the formation of diazo compounds. Subsequent 1,2-hydrogen shifts generally lead to the formation of alkenes as the final products. Cyclopropanes may also be formed as the result of intramolecular 1,3-C—H insertion reactions or when the original hydrazone substrate contains a remote alkenic group as a site for intramolecular cyclopropanation.10... 

Likewise, the sulfonylhydrazones 337a-c prepared from reactions of sodium benzenesulfinate with hydrazonoyl chlorides 20a-c in ethanol at room temperature cyclized in situ to give 338a, 338b, and 339, respectively (87MI1). 

H-cyclo-pentadien) 9-Diazo- E14h, 1015 (Sulfonylhydrazon-Pyrolyse)... 

Isoquinolin 4-Cyan-3-methyl-5,6,7,8-tetrahydro- E7b/2, 396 2-NR2-1 -[CH(OR)J — cyclohexen + H3C-C(NR2)=CH-CN Methan Cyclobutyl-diazo-phenyl-E14b, 1014 (Sulfonylhydrazon-Pyrolyse)... 

In contrast, salts 73b-i (R = ArS02) were obtained from the sulfonylhydrazones 70 (R = ArS02) or A-arylsulfonylisothiazolium-2-imines 7T by stirring 70% perchloric acid cooled to 0°C for lh (96ZOR1745). In Table 2 are given the isothiazolium-2-imines 71,71 and their salts 72,73, synthesized by this method. 

Most tosylhydrazone sodium salts could be usually Isolated from the reaction of the corresponding tosylhydrazones with sodium methoxide. However, a number of more functionalized hydrazone sodium salts, such as those derived from alkenyl aryl (25) sulfonyUiydrazones, ketone sulfonylhydrazones, and trimethylsi-lylacrolein sulfonylhydrazones, could not be isolated and an in situ salt generation procedure using NaHMDS was developed. A mixture of the desired hydrazones and NaHMDS was stirred at —78 °C then concentrated down before the addition of rhodium... 

C-atom 44, 576 2-siloxy-1,1,1 -trihalides, with 1 extra C-atom 43, 909 sulfonylhydrazones 44, 308 y-sulfonyl-5-lactones 44,192 2,2,2-trifluoroalcohols44, 542, 577 4-Oxo-1,3-heterocyclics... 

Li et al. [54] reported the Rh(III)-catalyzed oxidative C-H arylation of activated olefins with aryl-sulfonylhydrazones to give highly sought-after 1,2-dihydrophthalazines. The reaction demonstrated excellent functional group tolerance and scope, affording the products in generally very good yields. 

R,C=N-NS02Ar Salts of sulfonylhydrazones Photolysis or thermolysis diazoalkanes are intermediates R2C + N2 + ArS02 ... 

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