Epimerization in intramolecular carbanilide cyclization to hydantoins: A computational study

Young Dae Gong, Soo Kyung Kim, Sung eun Yoo, Mark J. Kurth

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

An efficient and diastereoselective route for the synthesis of 2,5,6,7-tetrasubstituted-1H-pyrrolo[1,2-c]imidazoles has been developed using intramolecular azomethine ylide cycloaddition and carbanilide cyclization. Ab initio calculations at the 6-31G (d,p) basis set reveal that the thermal stability of diastereomers determine the epimerization during the intramolecular carbanilide cyclization (→ hydantoin). These stereochemical results are consistent with an endo-like cycloaddition of a trans,anti-azomethine ylide followed by base-mediated C7a-H epimerization (C7a-Hβ → C7a-Hα) to deliver the thermodynamically preferred trans,anti,trans-(Ha-Hb, Hb-Hc, Hc-Hd)-pyrrolidine stereochemistry (3) which is ca. 20.1 kJ/mol more stable than the trans,anti,cis-pyrrolidine stereochemistry. In the case of 2-hydroxy-1-naphthaldehyde, naphthalene ring steric effects result in a different stereochemical arrangement about each pyrrolidine ring.

Original languageEnglish (US)
Pages (from-to)2477-2480
Number of pages4
JournalBulletin of the Chemical Society of Japan
Volume75
Issue number11
DOIs
StatePublished - 2002

ASJC Scopus subject areas

  • Chemistry(all)

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