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GaCl3-Catalyzed insertion of diazene derivatives into the cyclopropane ring
ISSN
0022-3263
Date Issued
2007
Author(s)
DOI
10.1021/jo0704816
Abstract
[GRAPHICS] GaCl3 has been found to efficiently catalyze the formal cycloadditions of diazene derivatives 6 onto 2-arylcyclopropane-1, 1-dicarboxylates 5, giving rise to the pyrazolidine derivatives 7. The insertion into the cyclopropane ring proceeds with complete regioselectivity to furnish 5-arylpyrazolidine-1,2,3,3-tetracarboxylates exclusively; however, the cis-configured azo compound N-phenyltriazolinedione gave the two possible regioisomeric pyrazolidine derivatives in ratios varying from 1:1.5 to 1:3. Conceivable mechanisms of these transformations are being discussed.