286936-09-2Relevant articles and documents
Asymmetric Total Synthesis of Cephanolide A
Gao, Shuanhu,He, Haibing,Zhang, Hongyuan
, p. 20417 - 20422 (2020)
The first asymmetric total synthesis of cephanolide A, a complex hexacyclic C18 dinorditerpenoid from cephalotaxus sinensis, was achieved. The synthesis features a convergent strategy, which provides a flexible approach to prepare the biogenetically cephalotaxus diterpenoids and structurally related derivatives for biological studies. A mild intramolecular Prins cyclization was developed to construct the central hexahydrofluorenol skeleton (A-B-C ring), which relies on the originally proposed hydroacylation strategy. A remote hydroxy group directed hydrogenation was applied to stereospecifically reduce the tetra-substituted enone unit. A sequence of ring forming steps, including lactonization, cation mediated etherification and Friedel–Crafts cyclization, was efficiently utilized to forge the cage-like skeleton.
Stereocontrolled Synthesis of (-)-Bactobolin A
Vojá?ková, Petra,Michalska, Lucyna,Ne?as, Marek,Shcherbakov, Dimitri,B?ttger, Erik C.,?poner, Ji?í,?poner, Judit E.,?venda, Jakub
, p. 7306 - 7311 (2020/05/25)
A stereoselective synthesis of the ribosome-binding antitumor antibiotic (-)-bactobolin A is reported. The presented approach makes effective use of (-)-quinic acid as a chiral pool starting material and substrate stereocontrol to establish the five contiguous stereocenters of (-)-bactobolin A. The key steps of the synthesis include a stereoselective vinylogous aldol reaction to introduce the unusual dichloromethyl substituent, a completely diastereoselective rhodium(II)-catalyzed C-H amination reaction to set the configuration of the axial amine, and an intramolecular alkoxycarbonylation to build the bicyclic lactone framework. The developed synthetic route was used to prepare 90 mg of (-)-bactobolin A trifluoroacetate in 10% overall yield.
Synthesis of the B-seco limonoid core scaffold
Bruss, Hanna,Schuster, Hannah,Martinez, Remi,Kaiser, Markus,Antonchick, Andrey P.,Waldmann, Herbert
, p. 194 - 208 (2014/02/14)
Synthetic investigations towards the structurally complex and highly decorated framework of B-seco limonoid natural products by means of a [3,3]-sigmatropic rearrangement are described. Detailed model studies reveal, that an Ireland-Claisen rearrangement can be employed to construct the central C9-C10 bond thereby giving access to the B-seco limonoid scaffold. However, application of the developed strategy ended up failing in more complex and sterically demanding systems.
Synthesis of the B-seco limonoid scaffold
Schuster, Hannah,Martinez, Remi,Bruss, Hanna,Antonchick, Andrey P.,Kaiser, Markus,Schuermann, Markus,Waldmann, Herbert
, p. 6545 - 6547 (2011/07/09)
The underlying stereochemically complex and densely functionalized scaffold of the B-seco limonoids was synthesized employing an Ireland-Claisen rearrangement as key transformation.
The synthesis of 2-oxyalkyl-cyclohex-2-enones, related to the bioactive natural products COTC and antheminone A, which possess anti-tumour properties
Arthurs, Claire L.,Morris, Gareth A.,Piacenti, Michela,Pritchard, Robin G.,Stratford, Ian J.,Tatic, Tanja,Whitehead, Roger C.,Williams, Katharine F.,Wind, Natasha S.
experimental part, p. 9049 - 9060 (2011/01/04)
The syntheses of five novel 2-oxyalkyl-cyclohex-2-enones, structurally related to the natural products COTC and antheminone A, are described. The target structures were selected in order to probe the influence of several key structural parameters on in vi
(-)-Quinic acid: a versatile precursor for the synthesis of analogues of 2-crotonyloxymethyl-(4R,5R,6R)-4,5,6-trihydroxycyclohex-2-enone (COTC) which possess anti-tumour properties
Arthurs, Claire L.,Lingley, Katharine F.,Piacenti, Michela,Stratford, Ian J.,Tatic, Tanja,Whitehead, Roger C.,Wind, Natasha S.
, p. 2410 - 2413 (2008/09/18)
Syntheses of three novel analogues of the Streptomyces metabolite COTC are described, using the versatile chiral pool starting material, (-)-quinic acid. The results of bioassays of the target compounds against two lung cancer cell lines, A549 and H460, a
Analogues of 2-crotonyloxymethyl-(4R,5R,6R)-4,5,6-trihydroxycyclohex-2-enone (COTC) with anti-tumor properties
Arthurs, Claire L.,Wind, Natasha S.,Whitehead, Roger C.,Stratford, Ian J.
, p. 553 - 557 (2007/10/03)
The syntheses of three novel analogues of the naturally occurring cytotoxic agent COTC are described and the results of bioassays of the target compounds against two lung cancer cell lines are presented.
Epoxidation of protected (1,4,5)-cyclohex-2-ene-triols and their acid hydrolysis to synthesize quercitols from D-(-)-quinic acid
Shih, Tzenge-Lien,Lin, Ya-Ling
, p. 1809 - 1817 (2007/10/03)
Highly stereoselective epoxidations have been achieved in both cyclohexylidene acetal and butane 2,3-bisacetal (BBA) protection of (1,4,5)-cyclohex-2-ene-triols. These epoxy derivatives are all derived from D-(-)-quinic acid and can be used for the synthe
Lithium enolates from a (-)-quinic acid-derived cyclohexanone with a β-alkoxy leaving group: Regioselective preparation and evaluation of enolate stability towards β-elimination
Murray, Lynne M.,O'Brien, Peter,Taylor, Richard J. K.,Wünnemann, Stefan
, p. 2597 - 2601 (2007/10/03)
Deprotonation of a (-)-quinic acid-derived ketone {(2S,3S,4aR,8R,8aS)-8- [(tert-butyl(dimethyl)silyl)oxy]-2,3-dimethoxy-2,3-dimethylhexahydro-1, 4-benzodioxin-6(5H)-one} using lithium hexamethyldisilazide (LHMDS) at -78°C gave one regioisomeric enolate. The regiocontrol is governed by the axial β-silyloxy substituent and the resulting lithium enolate is stable towards β-elimination at temperatures up to -40°C. It was found that the axial β-silyloxy group could be conveniently eliminated using 2.1equiv of LHMDS at 0°C for 1h and that an equatorial β-alkoxy group was much more resistant to β-elimination. A chiral lithium amide base was used to overturn the inherent regioselectivity of ketone deprotonation with LHMDS.
Stereoselective reactions of a (-)-quinic acid-derived enone: Application to the synthesis of the core of scyphostatin
Murray, Lynne M.,O'Brien, Peter,Taylor, Richard J. K.
, p. 1943 - 1946 (2007/10/03)
(Matrix presented) A (-)-quinic acid-derived enone, with the trans-1, 2-diol protected as a 2,3-dimethoxybutanediyldioxy ketal, provides an excellent template for further highly stereoselective elaboration as exemplified by its conversion into the core of
