Methyl 5-((2S,3S)-3-Methyl-3-(4-methyl-3-pentenyl)oxiran-2-yl)-3-(tosyloxy)pentanoate is an intermediate used in the synthesis of Juvenile Hormone B 3 (J211205), which is a sesquiterpenoid produced by the larval ring gland and adult corpus allatum (CA) of Drosophila melanogaster. Juvenile hormones regulate development, reproduction, diapause, and polyphenisms.