Selected PaperHiroshi
NishinoBulletin of the Chemical Society of Japan, 2024, 97, uoae011
https://doi.org/10.1093/bulcsj/uoae011
Advance access publication 29 January 2024
ArticlesSynthesis of dioxapropellanes using Mn(III)-based oxidative
tandem cyclization of tetracarbonyl compounds withdiarylethenes
Keisuke Shibuya, Ayaka Chikamatsu, Kazuki Hisano, Hiroshi Nishino*

Hiroshi Nishino
Hiroshi Nishino obtained his bachelor (1979) and MS degree in chemistry at Kumamoto University under
the supervision of Professor Kazu Kurosawa, and was appointed Assistant Professor (1981), Department ofChemistry, Faculty of Science, Kumamoto University. He received his Ph.D. degree (1988) in chemistry fromTohoku University supervised by Professor Sho Ito, and joined Professor Jay K. Kochi’s group (1988to 1989), University of Houston, U.S.A., then Associate Professor Tohru Fukuyama’s group (1989 to1990), Rice University, U.S.A. He returned to Kumamoto University in 1990, and was promoted toAssociate Professor in 1996, then full Professor (1999 to 2021), and is now Specially Appointed
Professor of Kumamoto University.

AbstractThe Mn(III)-based oxidation of tetracarbonyl compounds with 1,1-diarylethenes formed dioxapropellanes. The use of methylenebis(3-hydroxycyclohex-2-en-1-one)s as a tetracarbonyl compound led to the production of 3,4,5,6,7,9-hexahydro-8H-4a,9a-(epoxyethano)
xanthene-1,8(2H )-diones in good yields. Although the reaction competed with self-cyclization to form 3,5,6,7-tetrahydro-4H-spiro[benzofuran2,1′-cyclohexane]-2′,4,6′-triones, it could be controlled by adding the co-solvent formic acid at room temperature. The reactions of alkyl- andaryl-substituted methylenebis(3-hydroxycyclohex-2-en-1-one)s resulted in the corresponding dioxapropellanes as a diastereomixture. The
formation of diastereomers is explained by the steric hindrance of the intermediate carbocations during tandem cyclization. The reactions
using 2-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)butane-1,4-diones and 2,2′-methylenebis(3-hydroxycyclopent-2-en-1-one)s also
produced the corresponding dioxapropellanes. The structure determination of the products and the reaction pathway for the formation ofdioxapropellanes are discussed.
Keywords: dioxapropellanes, manganese(III) acetate, oxidative tandem cyclization.

Graphical Abstract

The Mn(III)-based oxidation of tetracarbonyl compounds with 1,1-diarylethenes formed dioxapropellanes. The use of methylenebis(3-hydroxycyclohex-2en-1-one)s led to the production of 3,4,5,6,7,9-hexahydro-8H-4a,9a-(epoxyethano)xanthene-1,8(2H )-diones in good yields. The reactions of alkyl- and arylsubstituted methylenebis(3-hydroxycyclohex-2-en-1-one)s resulted in the corresponding dioxapropellanes as a diastereomixture. The formation of thediastereomers is explained by the steric hindrance of the intermediate carbocations during the tandem cyclization.

[Received on 2 December 2023; revised on 16 January 2024; accepted on 19 January 2024; corrected and typeset on 11 March 2024]© The Author(s) 2024. Published by Oxford University Press on behalf of the Chemical Society of Japan. All rights reserved. For permissions, please e-mail:journals.permissions@oup.com

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Department of Chemistry, Graduate School of Science, Kumamoto University, Kurokami 2-39-1, Chûou-Ku, Kumamoto 860-8555, Japan*Corresponding author: Department of Chemistry, Graduate School of Science, Kumamoto University, Kurokami 2-39-1, Chûou-Ku, Kumamoto 860-8555,
Japan. Email: nishino@kumamoto-u.ac.jp