Total Synthesis of the <i>Schisandraceae</i>
Nortriterpenoid Rubriflordilactone A
作者:Guilhem Chaubet、Shermin S. Goh、Mujahid Mohammad、Birgit Gockel、Marie-Caroline A. Cordonnier、Hannah Baars、Andrew W. Phillips、Edward A. Anderson
DOI:10.1002/chem.201703229
日期:2017.10.9
Full details of the totalsynthesis of the Schisandraceae nortriterpenoid natural product rubriflordilactone A are reported. Palladium- and cobalt-catalyzed polycyclizations were employed as key strategies to construct the central pentasubstituted arene from bromoendiyne and triyne precursors. This required the independent assembly of two AB ring aldehydes for combination with a common diyne component
报道了五味子科降三萜类天然产物 rubriflordilactone A 的全合成细节。钯和钴催化的多环化被用作从溴戊二炔和三炔前体构建中心五取代芳烃的关键策略。这需要独立组装两个AB环醛以与共同的二炔组分结合。人们探索了许多模型系统来研究这两种方法,并建立了具有挑战性的苯并吡喃和丁烯内酯环的安装路线。
A New Insight into the Stereoelectronic Control of the Pd
<sup>0</sup>
‐Catalyzed Allylic Substitution: Application for the Synthesis of Multisubstituted Pyran‐2‐ones via an Unusual 1,3‐Transposition
作者:Zbyněk Brůža、Jiří Kratochvíl、Jeremy N. Harvey、Lubomír Rulíšek、Lucie Nováková、Jana Maříková、Jiří Kuneš、Pavel Kočovský、Milan Pour
DOI:10.1002/chem.201900323
日期:2019.6.18
Pyran‐2‐ones 3 undergo a novel Pd0‐catalyzed 1,3‐rearrangement to afford isomers 6. The reaction proceeds via an η2‐Pd complex, the pyramidalization of which (confirmed by quantum chemistry calculations) offers a favorable antiperiplanar alignment of the Pd−C and allylic C−O bonds (C), thus allowing the formation of an η3‐Pd intermediate. Subsequent rotation and rate‐limiting recombination with the
Stereoselective total synthesis of parthenolides indicates target selectivity for tubulin carboxypeptidase activity
作者:Robert R. A. Freund、Philipp Gobrecht、Zhigang Rao、Jana Gerstmeier、Robin Schlosser、Helmar Görls、Oliver Werz、Dietmar Fischer、Hans-Dieter Arndt
DOI:10.1039/c9sc01473j
日期:——
aldehydes was established to enable stereoselective access to α-(exo)-methylene γ-butyrolactones under mild conditions. Acid-labile functionality and chiral carbonyl compounds are tolerated. Excellent asymmetric induction was observed for β,β′-disubstituted α,β-epoxy aldehydes. These findings led to the enantioselective total synthesis of the sesquiterpene natural product (−)-parthenolide, its unnatural
Enantioselective Synthesis of the Predominant AB Ring System of the <i>Schisandra</i> Nortriterpenoid Natural Products
作者:Birgit Gockel、Shermin S. Goh、Emma J. Puttock、Hannah Baars、Guilhem Chaubet、Edward A. Anderson
DOI:10.1021/ol502027m
日期:2014.9.5
An enantioselectivesynthesis of the AB ring system common to the majority of the Schisandra nortriterpenoid natural products is reported. Key steps include a stereospecific ring opening of a trisubstitutedepoxide and the use of a β-lactone to enable installation of the gem-dimethyl functionality of the B ring. An acetalization strategy played a key role in a late-stage biomimetic AB ring bicyclization
loroxanthin (1) was accomplished by Horner-Wadsworth-Emmons reaction of C25-apocarotenal 8 having a silyl-protected 19-hydroxy moiety with C15-phosphonate 25 bearing a silyl-protected 3-hydroxy-ε-end group. Preparation of apocarotenal 8 was achieved viaStillecouplingreaction of alkenyl iodide 10 with alkenyl stananne 9, whereas phosphonate 25 was prepared through treatment of ally alcohol 23 with
氯黄素 ( 1 )的首次全合成是通过具有甲硅烷基保护的 19-羟基部分的 C 25 -胡萝卜醛8与带有甲硅烷基保护的 3-羟基-ε- 的C 15 -膦酸酯25的 Horner-Wadsworth-Emmons 反应完成的端组。apocarotenal 8的制备是通过烯基碘化物10与烯基锡烷9的Stille 偶联反应实现的,而膦酸酯25是通过烯丙醇23用亚磷酸三乙酯和ZnI 2处理制备的。烯丙醇23衍生自已知的 (3 R,6 R )-3-羟基 C 15 -醛20,其通过使用半制备手性 HPLC 柱直接光学拆分外消旋体20获得。