Radical olefination for the synthesis of bioactive compounds

Abstract

Olefins are of important as both intermediates in organic synthesis for transformation into various functional groups and biologically active compounds. There have been an enormous number of research efforts for the development of many methodologies to synthesize compounds in these classes. One of them was synthesized from one-pot. Horner-Witting procedure, combined methodology of the Horner-Witting reaction and then using neutral radical reaction for the preparation of stereospecific alkene was investigated without purification step in the mixture of erythro and threo diastereomers. After thorough investigations, under the elimination condition using an equivalent of Ph₂SiH₂ in the presence of radical initiators reacted with S-methyl dithiocarbonate or xanthate of the β-hydroxyphosphine oxide could not be efficiently used for the transformation to olefin due to the strength of C-P bond. However, these xanthates used as intermediates that embodied phosphorus reagents should offer a fertile area for future research both of deoxygenation and other related fields. Another approach was synthesized from syn-elimination of selenoxides via unsymmetrical diorganyl selenides. The novel, one-pot, mild and practical approaches for the synthesis of unsymmetrical diorganyl selenides were developed from two kinds of starting materials, organyl halides and alkyl diphenylphosphinites. Under the optimal condition, these starting materials reacted with PhSeSePh in the presence of In in CH₂CI₂ at reflux brought about successfully to exclusive unsymmetrical diorganyl selenides. Primary, secondary and tertiary alkyl and acyl phenyl selenides could be attained in moderate to excellent yields. Unsymmetrical diorganyl selenides led to the formation of olefin which could be applied to synthesize some biologically active natural products using H₂O₂ under mild and neutral conditions.