Cerium(IV) Ammonium Nitrate–Mediated Oxidation of Mono-aryl-substituted Methylenecyclobutanes: A Convenient Method for the Synthesis of Spirocyclobutyl-1,2-dioxethanes

Abstract

Cerium(IV) ammonium nitrate (CAN)-mediated oxidation of methylenecyclobutanes was investigated. Compared with the similar reactions of methylenecyclopropanes, the reaction products were quite different. Instead of the desired ring-enlarged product cyclopentanones, a cyclobutyl ring-intact product, spirocyclobutyl-1,2-dioxethane, was obtained. The structures of these spiroheterocycle-containing compounds are interesting, and the reactions are potentially valuable in both organic synthesis and mechanism research.

Keywords:

• CAN
• 1,2-dioxetane
• methylenecyclobutane
• oxidation
• spiro compound

ACKNOWLEDGMENTS

This work was supported by the Natural Scientific Foundation of Jiangsu Province (No. BK2010321), University Natural Scientific Foundation of Jiangsu Province (No. 09KJB150014), the 45th Postdoctoral Foundation of China (No. 20090451249), and the National Natural Scientific Foundation of China (Nos. 20633010 and 20773106).

Notes

^a Reaction conditions: 1a (0.3 mmol) and CAN (0.6 mmol) were stirred in 1 mL of solvent under different conditions.

^b The reaction was monitored by TLC (eluent: petroleum ether).

^c Isolated yields.

^d Unidentified complexes were observed.

^a Reaction conditions: 1 (0.3 mmol), CAN (0.6 mmol), CH₃CN (0.8 mL), and THF (0.2 mL), and the reactions were carried out in air at room temperature.

^b Isolated yields.

^c Unidentified complexes were observed.