Journal article
A general, regioselective synthesis of substituted benzocyclobutenedione monoacetals
Journal of organic chemistry, Vol.58(15), pp.3942-3952
07/01/1993
DOI: 10.1021/jo00067a029
Abstract
A general, regioselective synthesis of substituted benzocyclobutenedione monoacetals is reported. Palladium-catalyzed coupling of a variety of 4-chlorocyclobutenones with 3-(tri-n-butylstannyl)-3-cyclobutene-1,2-dione 2-(ethylene acetal) and heating up to 70–100 °C produces substituted benzocyclobutenedione monoacetals in good to excellent yields. This chemistry is presumed to proceed through palladium-catalyzed formation of a 3-(1-oxo-2-cyclobuten-4-yl)-3-cyclobutene-1,2-dione-2-(ethylene acetal) followed by a thermally induced ring opening to a dienyl ketene and subsequent six-electron electrocyclic ring closure and tautomerization. 2,3-Disubstituted 4-chlorocyclobutenones afford palladium intermediates which couple exclusively at the least-substituted allylic terminus. 2,3,4-Trisubstituted 4-chlorocyclobutenones have not been studied in detail; however, preliminary results suggest that regioselective allylic cross-coupling can be achieved. The methodology described provides an expedient and efficient route to previously difficult-to-prepare benzocyclobutenedione derivatives. These function as important synthetic intermediates in a variety of reactions developed in these and other laboratories. © 1993, American Chemical Society. All rights reserved.
Details
- Title: Subtitle
- A general, regioselective synthesis of substituted benzocyclobutenedione monoacetals
- Creators
- James P EdwardsDamian J KrysanLanny S Liebeskind
- Resource Type
- Journal article
- Publication Details
- Journal of organic chemistry, Vol.58(15), pp.3942-3952
- Publisher
- American Chemical Society
- DOI
- 10.1021/jo00067a029
- ISSN
- 0022-3263
- eISSN
- 1520-6904
- Language
- English
- Date published
- 07/01/1993
- Academic Unit
- Stead Family Department of Pediatrics; Microbiology and Immunology; Infectious Disease (Pediatrics)
- Record Identifier
- 9984297322802771
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