Synthesis 2005(5): 731-740  
DOI: 10.1055/s-2005-861807
PAPER
© Georg Thieme Verlag Stuttgart · New York

One-Pot Synthesis of Spirofuran and Benzocycloalka[1,2-b]furan Derivatives Using Manganese(III)-Mediated Oxidative Radical Cyclization

Reika Fujinoa, Hiroshi Nishino*b
a Department of Materials and Life Science, Graduate School of Science and Technology, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, Japan
b Department of Chemistry, Faculty of Science, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, Japan
Fax: +81(96)3423374; e-Mail: nishino@sci.kumamoto-u.ac.jp;
Further Information

Publication History

Received 28 September 2004
Publication Date:
09 February 2005 (online)

Abstract

New spiro[furan-2(3H),1′-(benzocycloalkane)] derivatives were obtained by the oxidation of methylenebenzocycloalkanes with manganese(III) acetate in the presence of 1,3-dicarbonyl compounds. A similar oxidation of the benzocycloalkene derivatives produced the functionalized benzocycloalka[1,2-b]furans in good yields. However, 1-benzyl-3,4-dihydronaphthalene gave both the corresponding spirofuran and benzocyclohexa[1,2-b]furan under the same oxidation conditions. The acid-catalyzed ring-opening reaction of the spirofurans and benzocycloalka[1,2-b]furans was also investigated.

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PM3 calculation was performed by CAChe version 4.9.3.

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Crystal Structure Analysis Package, Molecular Structure Corporation: 1985 and 1992.