Reaction of E-2-arylidene-1-indanones, Z-aurones, Z-1-thioaurones and Z-2-arylidene-2,3-dihydro-1H-indol-3-ones with diazomethane

1,3-Dipolar cycloaddition of E-2-arylidene-1-indanones 1a-h and Z-aurones 3 a-c with diazomethane provided trans-spiro-1-pyrazolines 2a-h and 4a-c, res pectively, as sole products. However, the same cycloaddition of Z-1-thioaur ones 5a-f afforded a mixture of Z-alpha-methyl-1-thioaurones 6a-f and trans -cyclopropane derivatives 7a-f as a result of the spontaneous denitrogenati on of the initially formed l-pyrazolines. Similar reaction of Z-2-arylidene -2,3-dihydro-1H-indol-3-ones 8a,b and diazomethane yielded trans-cyclopropa nes 9a,b. Structure and stereochemistry of the compounds synthesized have b een elucidated by nmr spectroscopic measurements.