OZONOLYSIS OF TETRAHYDROCHROMANS . FORMATION OF GLYCOLS AND NORMAL OZONOLYSIS PRODUCTS

The ozonolysis of tetrahydrochromans followed by work-up with zinc and acetic acid gives varying amounts of 6-ketononanolides, the expected product, and trans-9, 10-dihydroxyhexahydrochromans, depending on reaction conditions. Ozonolysis in methanol gives 9-methoxy-10-hydroxyhexahydrochroman as the principal product. It is postulated that ozonolysis of enol ethers such as tetrahydrochromans can give either ozonides and/or peroxidic products which are converted into the expected dicarbonyl products or epoxy ethers which are solvolyzed to give dihydroxy or alkoxyhydroxy ethers. Electronic factors leading to epoxy ether formation in ozonolysis and the problem of the assignment of stereochemistry to the isolated dihydroxy and alkoxyhydroxy ethers are discussed. © 1969, American Chemical Society. All rights reserved.