Chloral Hydrate as a Water Carrier for the Efficient Deprotection of Acetals, Dithioacetals, and Tetrahydropyranyl Ethers in Organic Solvents

Abstract

The efficient deprotection of several acetals, dithioacetals, and tetrahydropyranyl (THP) ethers under ambient conditions, using chloral hydrate in hexane, is described. Excellent yields were realized for a wide range of both aliphatic and aromatic substrates. The method is characterized by mild conditions (room temperatures or below), simple workup, and the ready availability of chloral hydrate. High chemoselectivity was also observed in the deprotection, acetonides, esters, and amides being unaffected under the reaction conditions. Products were generally purified chromatographically and identified spectrally. These results constitute a novel addition to current methodology involving a widely employed deprotection tactic in organic synthesis. It seems likely that the mechanism of the reaction involves adsorption of the substrate on the surface of the sparingly soluble chloral hydrate.

GRAPHICAL ABSTRACT

Keywords:

• Acetals
• chemoselective
• deprotection
• hydrolysis
• nonaqueous