Total synthesis of resolvin E2

Resolvin E2 (2) was synthesized stereoselectively using the C1-8 and C15-20 aldehydes 6 and 9, which were connected to the C9-14 fragment by using Wittig reactions. The aldehyde 6 was prepared from the γ-silyl alcohol (S)-20 by a sequence of reactions involving ozonolysis, oxidation with NaIO4, and the Wittig reaction of the resulting aldehyde with Ph3PCHCHO, whereas the aldehyde 9 was synthesized from the corresponding γ-silyl alcohol through epoxidation, reaction with Et2AlCN, and reduction with DIBAL-H.