Shigeo Kohmoto

New chemistry of zwitterionic peroxides arising by photooxygenation of enol ethers

Abstract The rosebengal-sensitized photooxygenation of 2-methoxynorborn-2-ene( 1 )in acetaldehyde gave cis -1-carboxaldehyde-3-carbomethoxycyclopentane (31%) and the cis and trans -Me derivatives of the cis -fuscd exo -1,2,4-trioxanes arising by addition of a molecule of oxygen and acetaldehyde to 1 at C3 and C2 respectively (13%) Similar photooxygenation of 2-(methoxymethylidene)adamantane in the presence of acetaldehyde, propionaldehyde and pivalaldehyde gave adamantanone (31–42%), and the cis and trans tricylo[3.3.1.1 3,7 ]decane-2-spiro-6-[3-alkyl-5-methoxy-1,2,4-trioxanes] in yields of 32–53% Trioxane formation under similar conditions was experienced for 1,1-di-t-butyl-2-methoxyethene and 2-(methylmercaptomethylidene) adamantane. The results are discussed in terms of an intermediate zwitterionic peroxide which can either close directly to a 1,2-dioxetane or, if aldehyde is present, condense across the CO function giving the 1,2,4-trioxane.

An unusual stereospecific epoxidation with “per-amberlyst 15®”

Abstract 4-Methyl-4-naphthoquinol and its 5-methyl derivative on treatment with per-Amberlyst 15 are converted to the corresponding cis-2,3-epoxides in high yields. The latter structure was determined by X-ray crystallography.

High-performance liquid chromatography of some novel diastereomeric tricyclic 1,2,4-trioxanes

Abstract A series of 4a, 10b-dihydronaphtho-[2,1-e]-1,2,4-trioxanes were examined by h.p.l.c. Compounds existing as a pair of diastereomers are only resolved when hydrogen is a substituent at the C3 position. The separations actually observed may arise from conformational differences rather than simple diastereoisomerism.