Translation of pseudo-cross-conjugation into chemistry: cycloadditions of mesomeric betaines to the new ring system spiro[indazole-3,3'-pyrrole]

Andreas Schmidt; Tobias Habeck; Anika Sabine Lindner; Bohdan Snovydovych; Jan Christoph Namyslo; Arnold Adam; Mimoza Gjikaj

doi:10.1021/jo062391r

Translation of pseudo-cross-conjugation into chemistry: cycloadditions of mesomeric betaines to the new ring system spiro[indazole-3,3'-pyrrole]

J Org Chem. 2007 Mar 16;72(6):2236-9. doi: 10.1021/jo062391r. Epub 2007 Feb 24.

Authors

Andreas Schmidt¹, Tobias Habeck, Anika Sabine Lindner, Bohdan Snovydovych, Jan Christoph Namyslo, Arnold Adam, Mimoza Gjikaj

Affiliation

¹ Institute of Organic Chemistry, Leibnizstrasse 6, Clausthal University of Technology, D-38678 Clausthal-Zellerfeld, Germany. schmidt@ioc.tu-clausthal.de

PMID: 17319725
DOI: 10.1021/jo062391r

Abstract

Indazolium-3-amidates (X-ray analysis), readily available on trapping the N-heterocyclic carbene indazol-3-ylidene with isocyanates, underwent [3+2]-cycloadditions with activated triple bonds to spiro[indazole-3,3'-pyrroles]. A combination of NMR techniques such as heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), nuclear Overhauser enhancement spectroscopy (NOESY), and 1H/15N correlations were applied to elucidate the structures of the cycloadducts.