Further Investigations into the Regioselectivity of 6,7-Indole Aryne Cyclo­additions with 2-Substituted Furans: Remarkable Contrasteric Preference Depends­ on Pyrrole and Benzene Ring Substitution

Alok Nerurkar; Nalin Chandrasoma; Lincoln Maina; Allen Brassfield; Diheng Luo; Neil Brown; Keith R. Buszek

doi:10.1055/s-0033-1338911

Synthesis, Inhaltsverzeichnis

Synthesis 2013; 45(13): 1843-1852
DOI: 10.1055/s-0033-1338911

paper

Further Investigations into the Regioselectivity of 6,7-Indole Aryne Cycloadditions with 2-Substituted Furans: Remarkable Contrasteric Preference Depends on Pyrrole and Benzene Ring Substitution

Autor*innen

Alok Nerurkar

^aDepartment of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110, USA
Nalin Chandrasoma

^aDepartment of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110, USA
Lincoln Maina

^aDepartment of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110, USA
Allen Brassfield

^aDepartment of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110, USA
Diheng Luo

^aDepartment of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110, USA
Neil Brown

^aDepartment of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110, USA

^bCenter of Excellence in Chemical Methodologies and Library Development (KU-CMLD), University of Kansas, Delbert M. Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, KS 66047, USA Fax: +1(816)2355502 eMail: buszekk@umkc.edu
Keith R. Buszek*

^aDepartment of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110, USA

^bCenter of Excellence in Chemical Methodologies and Library Development (KU-CMLD), University of Kansas, Delbert M. Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, KS 66047, USA Fax: +1(816)2355502 eMail: buszekk@umkc.edu

Abstract

Alle Artikel dieser Rubrik

This paper is warmly dedicated to Professor Scott Denmark on the occasion of his 60^th birthday.

Abstract

A series of related 6,7-dibromoindole compounds were prepared to study the effects of pyrrole and benzene ring substitution patterns on the regioselectivity of 6,7-indole aryne cycloadditions with 2-tert-butylfuran. The arynes were generated by our metal–halogen exchange/elimination protocol. The results of this investigation reveal that substitution at the 3-position on the indole ring in particular results in remarkable regiocontrol that favored the contrasteric products. Aromatic conjugation at this site significantly enhanced this effect. However, the presence of most 4- or 5-substituents generally resulted in markedly reduced selectivity. Exceptions in this latter series included the 4-ethyl and 4-iodo cases both of which also gave predominantly contrasteric products even in the absence of a beneficial C-3 substituent.

Key words

alkaloids - arynes - cycloaddition - indoles - regioselectivity

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Referenzen

References

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Further Investigations into the Regioselectivity of 6,7-Indole Aryne Cyclo­additions with 2-Substituted Furans: Remarkable Contrasteric Preference Depends­ on Pyrrole and Benzene Ring Substitution

Autor*innen

Further Investigations into the Regioselectivity of 6,7-Indole Aryne Cycloadditions with 2-Substituted Furans: Remarkable Contrasteric Preference Depends on Pyrrole and Benzene Ring Substitution