η ⁶‐(1‐Oxobenzocyclobutene)tricarbonylchromium(0)

Preparation, Reduction, and Ring-Opening/Cycloaddition Chemistry of the 1-Hydroxybenzocyclobutene Complex

authored by

Michael Brands, Hans G. Wey, Rainer Krömer, Carl Krüger, Holger Butenschön

Abstract

The syntheses of the tricarbonylchromium complexes 2 and 3 of 1‐oxobenzocyclobutene and 1‐hydroxybenzocyclobutene are described. Alcoholate 6 of 3 undergoes a ring opening to the corresponding ortho‐quinodimethane intermediate between −30 and −20°C, which is trapped by dienophiles with high diastereoselectivity. While with most dienophiles products with a 1,2‐cis configuration (7, 8, 10) are formed, vinyl sulfones react in an exo‐selective cycloaddition with formation of 1,2‐trans‐configurated cycloadducts (12, 13). The configuration of the cycloadduct with phenyl vinyl sulfone is confirmed by an X‐ray crystal structure analysis. As one of the important aspects of the chemistry of benzocyclobutene complexes is the chirality of compounds like 2 and 3, the enantiomeric resolution has been achieved via the semioxamazones of ketone 2.

External Organisation(s)

Max-Planck-Institut für Kohlenforschung

Type

Article

Journal

Liebigs Annalen

Volume

1995

Pages

253-265

No. of pages

13

ISSN

0947-3440

Publication date

27.01.1995

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Chemistry

Electronic version(s)

https://doi.org/10.1002/jlac.199519950235 (Access: Unknown)