Addition and Ring Expansion Reactions of Tricarbonyl-(1,2-dioxobenzocyclobutene)chromium(0) with Carbon Nucleophiles

Unexpected Formation of Benzocycloheptene Derivatives and the First Head-to-Head Coupling of Two Methoxyallene Molecules

authored by: Beate Voigt, Michael Brands, Richard Goddard, Rudolf Wartchow, Holger Butenschön
Abstract: Addition of carbon nucleophiles to (benzocyclobutenedione)tricarbonylchromiuni(0) (4) results in the formation of exo mono- and diadducts as well as 1,2-diketones as the consequence of proximal ring-opening reactions. In one case the unexpected formation of benzocycloheptenedione complexes is observed. Treatment of 4 with an excess of 1-ethoxy-1-lithioethene gives the product of a dianionic oxy-Cope rearrangement followed by an intramolecular aldol addition. This is also the case with lithiated methoxyallene, and as the result the first head-to-head coupling product 12 of two methoxyallene molecules is isolated in good yield. 12 is used as a diene in Diels-Alder cycloadditions, and its molecular structure is compared to that of the similar molecule 13, lacking the two exo methylene substitutents.
Organisation(s): Institute of Organic Chemistry
External Organisation(s): Max-Planck-Institut für Kohlenforschung
Type: Article
Journal: European Journal of Organic Chemistry
Pages: 2719-2727
No. of pages: 9
ISSN: 1434-193X
Publication date: 23.12.1998
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Organic Chemistry
Electronic version(s): https://doi.org/10.1002/(SICI)1099-0690(199812)1998:12<2719::AID-EJOC2719>3.0.CO;2-H (Access: Unknown)

BibTeX

@article{2f8d9b1262ee4446a7ad9cef83353884,
title = "Addition and Ring Expansion Reactions of Tricarbonyl-(1,2-dioxobenzocyclobutene)chromium(0) with Carbon Nucleophiles: Unexpected Formation of Benzocycloheptene Derivatives and the First Head-to-Head Coupling of Two Methoxyallene Molecules",
abstract = "Addition of carbon nucleophiles to (benzocyclobutenedione)tricarbonylchromiuni(0) (4) results in the formation of exo mono- and diadducts as well as 1,2-diketones as the consequence of proximal ring-opening reactions. In one case the unexpected formation of benzocycloheptenedione complexes is observed. Treatment of 4 with an excess of 1-ethoxy-1-lithioethene gives the product of a dianionic oxy-Cope rearrangement followed by an intramolecular aldol addition. This is also the case with lithiated methoxyallene, and as the result the first head-to-head coupling product 12 of two methoxyallene molecules is isolated in good yield. 12 is used as a diene in Diels-Alder cycloadditions, and its molecular structure is compared to that of the similar molecule 13, lacking the two exo methylene substitutents.",
keywords = "Benzocyclobutene, Benzocycloheptenedione, Chromium, Dianionic Oxy-Cope Rearrangement, Methoxyallene",
author = "Beate Voigt and Michael Brands and Richard Goddard and Rudolf Wartchow and Holger Butensch{\"o}n",
year = "1998",
month = dec,
day = "23",
doi = "10.1002/(SICI)1099-0690(199812)1998:12<2719::AID-EJOC2719>3.0.CO;2-H",
language = "English",
pages = "2719--2727",
journal = "European Journal of Organic Chemistry",
issn = "1434-193X",
publisher = "Wiley-VCH Verlag",
number = "12",
}