Diazoverbindungen, 65 Isomerisierungen im System 4-Diazo-1-buten/2.3-Diazabicyclo[3.1.0]hex-2-en/1.4-Dihydropyridazin/Diazo Compounds, 65 Isomerization Reactions in the System 4-Diazo-1-butene/2.3-Diazabicyclo[3.1.0]hex-2-ene/1.4-Dihydropyridazine

Abstract

<jats:title>Abstract</jats:title><jats:p> (Diazomethyl)diphenylphosphine oxide (2a) adds onto the 1-cyclopropene phosphonates 1a and c under formation of the 2.3-diazabicyclo[3.1.0]hex-2-enes 3a and c. 3a is easily converted into the 1.4-dihydropyridazine 5a. On the other hand the reaction of 1b with 2a directly affords the 1.4-dihydropyridazine 5b. The 2.3-diazabicyclo[3.1.0]hex-2-enes 3a and c isomerize to the allyl diazomethanes 4a and c on heating in benzene. In the case of the reactions 2b+1b as well as 6+1a the direct formation of allyl diazo compounds (4d and 8a respectively) is observed. In a novel reaction 9-diazofluorene (6) yields the 1.3-butadiene 9 when reacted with the cyclo-propene 1b.</jats:p>