中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | (2R,3S)-1,4-bis[(4S)-4-isopropyl-2-oxo(1,3-oxazolidin-3-yl)]-2,3-bis[(3,4-methylenedioxyphenyl)methyl]butane-1,4-dion | 161815-11-8 | C32H36N2O10 | 608.645 |
—— | (2R,3R)-1,4-bis[(4S)-4-isopropyl-2-oxo(1,3-oxazolidin-3-yl)]-2,3-bis[(3,4-methylenedioxyphenyl)methyl]butane-1,4-dione | 161745-71-7 | C32H36N2O10 | 608.645 |
—— | (R)-3-Benzo[1,3]dioxol-5-ylmethyl-4-((S)-4-isopropyl-2-oxo-oxazolidin-3-yl)-4-oxo-butyric acid tert-butyl ester | 196804-99-6 | C22H29NO7 | 419.475 |
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.