Triphenylphosphine → Triphenylphosphine Oxide

Participants

Reaction Steps

To a mixture of 4.2 g. of [1(S),4R]-1-[3-(benzoylthio)-2-methyl-1-oxopropyl]-4-hydroxy-L-proline, methyl ester, 3 g. of 2-(dimethoxymethyl)-phenol, 4.6 g. of triphenylphosphine dissolved in 15 ml. of tetrahydrofuran there is added 3.1 g. of diethylazodicarboxylate dissolved in 5 ml. of tetrahydrofuran (nitrogen atmosphere). The mixture becomes warm. The solution is stirred overnight. Addition of ether/petroleum ether yields 1.1 g. of dicarbethoxyhydrazine which is filtered off. Addition of more petroleum ether to the filtrate furnishes oily triphenylphosphine oxide which on trituration with ether turns solid; 2.5 g. The filtrate is absorbed on Baker silica and flash chromatographed. Elution with 85% ether - 10% petroleum ether elutes the pure product in six fractions, 250 ml. each, yielding 2.99 g. of [1(S),4S]-1-[3-(benzoylthio)-2methyl-1-oxopropyl]-4-[2-(dimethoxymethyl)phenoxy]-L-proline, methyl ester. A small sample is characterized and analyzed as its 2,4-dinitrophenyl hydrazine derivative.

Provenance & Evidence