ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Exo-Stereoselective 1,3-Dipolar Cycloadditions of Nitrile Oxides to Endo-7-(R¹,R²- methylene)bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylates

V. Ondruš, Ľ. Fišera, P. Ertl, and N. Prónayová

Department of Organic Chemistry, Faculty of Chemical Technology, Slovak Technical University, SK-812 37 Bratislava

Abstract: 1,3-Dipolar cycloaddition of arylnitrile oxides to endo-N-(3,5-dichlorophenyl)imide 7-R¹,R²- methylene)bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylates (R¹,R²= phenyl, methyl, 2-thienyl, 2-furyl) led exclusively to endo-exo cycloadducts. Semiempirical quantum-mechanical methods AMI showed that the exclusive exo-1,3-dipolar cycloaddition can be rationalized through the secondary orbital interaction between 1,3-dipole and π orbital of the exo-cyclic C=C double bond in the methylene bridge. Both endo-syn-exo and ende-anti-exo cycloadducts were formed in the ratio 50 : 50 in the case of R¹≠R².

Full paper in Portable Document Format: 486a399.pdf

Chemical Papers 48 (6) 399–403 (1994)