中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | (S)-3-Benzo[1,3]dioxol-5-ylmethyl-4-((R)-4-benzyl-2-oxo-oxazolidin-3-yl)-4-oxo-butyric acid tert-butyl ester | 196804-98-5 | C26H29NO7 | 467.519 |
A simple procedure for the asymmetric synthesis of lignans via chiral β-benzyl-γ-butyrolactones has been developed. The key benzylbutyrolactone intermediates were efficiently synthesized using a six-step procedure, starting from 3,4-(methylenedioxy)cinnamic acid. The key step in this sequence was a highly diastereoselective alkylation of an N-acyloxazolidinone enolate. The resulting β-benzyl-γ-butyrolactones were subsequently transformed into the benzylidene lignans gossypifan and savinin (hibalactone) via aldol condensation–dehydration reactions, and into the dibenzylbutyrolactone lignan 4′-demethylyatein, through alkylation. Oxidation of 4′-demethylyatein with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) afforded cis-and trans-benzylidenebenzylbutyrolactones, whereas oxidation with DDQ/TFA gave 4′-demethyl-deoxyisopodophyllotoxin. Keywords: lignans, synthesis, asymmetric, biosynthesis, oxidation, benzylbutyrolactones.