Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Cycloaddition of a Very Reactive Cyanovinylcarbene with Benzene and 3,4-Dichlorocyclobutene. Molecular and Crystal Structure of 2,3-Dichloro-5-(1-cyano-2-methyl-1-propenyl)-5-housanecarbonitrile and 7-(1-Cyano-2-methyl-1-propenyl)-7-norcaradienecarbonitrileThe cyanovinylcarbene 2 has been generated by photolysis of 3,3-dimethyl-3H-pyrazole-4,5-dicarbonitril (1) and the cycloaddition products with benzene and with 3,4-dichlorocyclobutene have been isolated. The molecular structures of the cycloaddition products 7-(1-cyano-2-methyl-1-propenyl)-7-norcaradienecarbonitrile (3) and 2,3-dichloro-5-(1-cyano-2-methyl-1-propenyl)-5-housanecarbonitrile (4) were determined by X-ray analyses. The bridging bond of the bicyclo[2.1.0]pentane group in 4 is shortened to 1.515 Å by the electronic interaction of this group with the cyano substituent. The vinyl substituent has no influence because of perpendicular orientation.
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