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
diastereoselective synthesis of 4-vinyl oxazolines syn-2 was developed based on an acid-catalyzed cyclization of bistrichloroacetimidates (E)-1. The reaction likely involves an allyl carbenium ion intermediate in which the adjacent stereocenter directs the stereoselectivity for C–N bond formation. Oxazolines syn-2 were transformed to C-quaternary threoninol, threoninal, and threoninederivatives which can be
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