Five new compounds, including four C-17 gamma-lactones, dihydroisoobtusilactone (A), dihydroobtusilactorie (2), 3-epilitsenolide D-2 (3), and 3-epilitsenolide D-1 (4), and one furanone alseodafuranone (V were isolated from the root and stem of Alseodaphne andersonii. Their structures were elucidated mainly by spectral analysis (NMR and MS) and partially by chemical correlation.
Stereopure 1,3-butadiene-2-carboxylates and their conversion into non-racemic α-alkylidenebutyrolactone natural products by asymmetric dihydroxylation
摘要:
Dienoic esters 1 with the four possible permutations of the C=C configurations were prepared in two steps via non-stereoselective aldol additions followed by stereospecific beta -eliminations. Sharpless dihydroxylations of these esters yielded natural and unnatural alpha -alkylidene-beta -hydroxybutyrolactones 2. Among these were synthetic dihydromahubanolide B (cis,Z-2a), isodihydromahubanolide B (cis,E-2a) and, for the first time, litsenolide D-1 (ent-trans,Z-2b) and the enantiomer trans,E-2b of litsenolide D-2. Competitively, dihydroxyesters 10 were formed. (C) 2001 Elsevier Science Ltd. Al rights reserved.
The first total syntheses of 3-epi-litsenolide D2 and its enantiomer lincomolide A were achieved. The synthetic highlights of our approach include olefin cross metathesis and bromine addition to the generated double bond, followed by the regioselective HBr-elimination and intramolecular carbonylation using bis(triphenylphosphine)dicarbonylnickel. This investigation also revealed that the previously
首次合成了3- epi- litsenolide D 2及其对映异构体lincomolideA。我们方法的合成亮点包括烯烃交叉复分解和向生成的双键中添加溴,然后使用双(三苯基膦)二羰基镍进行区域选择性HBr消除和分子内羰基化。这项研究还表明,应该修改以前报告的3- epi- litsenolide D 2的特定旋光度。
Stereopure 1,3-butadiene-2-carboxylates and their conversion into non-racemic α-alkylidenebutyrolactone natural products by asymmetric dihydroxylation
作者:Christian Harcken、Reinhard Brückner
DOI:10.1016/s0040-4039(01)00598-6
日期:2001.6
Dienoic esters 1 with the four possible permutations of the C=C configurations were prepared in two steps via non-stereoselective aldol additions followed by stereospecific beta -eliminations. Sharpless dihydroxylations of these esters yielded natural and unnatural alpha -alkylidene-beta -hydroxybutyrolactones 2. Among these were synthetic dihydromahubanolide B (cis,Z-2a), isodihydromahubanolide B (cis,E-2a) and, for the first time, litsenolide D-1 (ent-trans,Z-2b) and the enantiomer trans,E-2b of litsenolide D-2. Competitively, dihydroxyesters 10 were formed. (C) 2001 Elsevier Science Ltd. Al rights reserved.
Chemical Constituents from <i>Alseodaphne andersonii</i>
Five new compounds, including four C-17 gamma-lactones, dihydroisoobtusilactone (A), dihydroobtusilactorie (2), 3-epilitsenolide D-2 (3), and 3-epilitsenolide D-1 (4), and one furanone alseodafuranone (V were isolated from the root and stem of Alseodaphne andersonii. Their structures were elucidated mainly by spectral analysis (NMR and MS) and partially by chemical correlation.