Preparation of alkyl iodides and alkyl phenyl selenides from alkyl diphenylphosphinites

Abstract

The mild and efficient approaches for preparing alkyl phenyl selenides and alkyl iodides from alkyl diphenylphosphinites were developed. In the case of the synthesis of alkyl phenyl selenides, 1-adamantyl diphenylphosphinite was utilized as a model substrate. The combination of PhSeSePh and indium at reflux afforded alkyl phenyl selenides in high yield. Appealingly, tertiary selenides also worked well under this optimal condition. The reaction of an optically active substrate distinctly revealed that this mechanism took place via SN2 displacement. Considering to iodination of alkyl diphenylphosphinites, cis-oleyl diphenylphosphinite was selected as a chemical model. The use of only I₂ as an iodinating agent could complete the reaction in short period of time and acquired high yields of the desired products even in the case of tertiary alkyl iodides. Furthermore, in situ iodination of alcohols through alkyl diphenylphosphinites was also preliminarily investigated to develop and simplify this protocol. The I₂/ClPPh₂ system in the presence of pyridine in CH₂Cl₂ at RT was affirmed as the optimal reaction condition. The model iodides, 1-hexyl iodide and 1-octyl iodide, were provided in high yields.