Efficient and selective oxidative deprotection of tetrahydropyranyl ethers, ethylene acetals and ketals with silver and sodium bromates in the presence of aluminum chloride

Abstract

Primary and secondary tetrahydropyranyl (THP) ethers are efficiently transformed to their carbonyl compounds with AgBrO3 and NaBrO3/AlCl3. Ethylene acetals and ketals are transformed to their carboxylic acids and ketones respectively with AgBrO3/AlCl3 in refluxing acetonitrile. AgBrO3/AlCl3 is also able to transform ethylene acetals to aldehydes in refluxing carbon tetrachloride in high yields. In refluxing acetonitrile, ethylene acetals and ketals are transformed to aldehydes and ketones with NaBrO3/AICI3. We have also found that tetrahydropyranyl ethers are oxidized selectively in the presence of ethylene acetals and ketals with these reagents.