Tetraarylphosphonium salts as soluble supports for oxidative catalysts and reagents.

Tetraarylphosphonium (TAP)-supported DMSO, TEMPO, and DIB reagents were synthesized and used for the oxidation of alcohols, including Swern oxidation and for the alpha-acetoxylation of ketones. By taking advantage of the predictable solubility properties of the TAP unit, simple precipitation and filtration of the phosphonium moiety permit complete separation of the desired oxidation products. This paper describes the preparation of these three TAP-supported oxidative reagents and their activity in the aforementioned oxidative transformations.

Tetraarylphosphonium-supported carbodiimide reagents: synthesis, structure optimization and applications.

New tetraarylphosphonium (TAP)-supported alkyl- and arylcarbodiimides were synthesized and used as coupling reagents for esterification reactions, amidation reactions and dehydration reactions of hydroxyesters. Taking advantage of the solubility properties imparted by the tetraarylphosphonium unit, a simple precipitation and filtration allowed complete separation of the urea by-products. This paper describes the structure optimization study of the various TAP-supported carbodiimide reagents to obtain the desired reactivity and solubility profile.