124655-05-6Relevant articles and documents
18O assisted analysis of a γ,δ-epoxyketone cyclization: Synthesis of the C16-C28 fragment of ammocidin D
Chau, Stephen T.,Hayakawa, Yoichi,Sulikowski, Gary A.
supporting information; experimental part, p. 756 - 759 (2011/04/24)
The C16-C28 fragment common to the cytotoxic macrolide ammocidin D has been prepared by a stereospecific 5-exo closure of a γ,δ-epoxyketone followed by a rearrangement to a pyran acetal. The reaction pathway was traced by 18O labeling of the ke
Total synthesis of phorboxazole A via de novo oxazole formation: Strategy and component assembly
Wang, Bo,Hansen, T. Matthew,Wang, Ting,Wu, Dimao,Weyer, Lynn,Ying, Lu,Engler, Mary M.,Sanville, Melissa,Leitheiser, Christopher,Christmann, Mathias,Lu, Yingtao,Chen, Jiehao,Zunker, Nicholas,Cink, Russell D.,Ahmed, Feryan,Lee, Chi-Sing,Forsyth, Craig J.
scheme or table, p. 1484 - 1505 (2011/04/16)
The phorboxazole natural products are among the most potent inhibitors of cancer cell division, but they are essentially unavailable from natural sources at present. Laboratory syntheses based upon tri-component fragment coupling strategies have been developed that provide phorboxazole A and analogues in a reliable manner and with unprecedented efficiency. This has been orchestrated to occur via the sequential or simultaneous formation of both of the natural product's oxazole moieties from two serine-derived amides, involving oxidation-cyclodehydrations. The optimized preparation of three pre-assembled components, representing carbons 3-17, 18-30, and 31-46, has been developed. This article details the design and syntheses of these three essential building blocks. The convergent coupling approach is designed to facilitate the incorporation of structural changes within each component to generate unnatural analogues, targeting those with enhanced therapeutic potential and efficacy.
Au-catalyzed cyclization of monopropargylic triols: An expedient synthesis of monounsaturated spiroketals
Aponick, Aaron,Li, Chuan-Ying,Palmes, Jean A.
supporting information; experimental part, p. 121 - 124 (2009/07/11)
The gold-catalyzed cyclization of monopropargylic triols to form olefin-containing spiroketals is reported. The reactions are rapid and high yielding when 2 mol % of the catalyst generated in situ from Au[P(t-Bu) 2(o-biphenyl)]CI and AgOTf is e
Total synthesis of (-)-bitungolide F
Su, Yingpeng,Xu, Yanfen,Han, Junjie,Zheng, Jiyue,Qi, Jing,Jiang, Tuo,Pan, Xinfu,She, Xuegong
supporting information; experimental part, p. 2743 - 2749 (2009/09/05)
An efficient total synthesis of (-)-bitungolide F (6) in 17 steps and 20.1% yield is described herein. Key steps involve a Myers asymmetric alkylation to introduce the C6 methyl with proper stereochemistry, a Claisen-like cyclization to construct the α,β-unsaturated β-lactone and a Julia-Kocienski olefination to assemble the conjugated diene moiety.
Total synthesis of (-)-bitungolide F and determination of its absolute stereochemistry
Ghosh, Subhash,Kumar, Soma Uday,Shashidhar
, p. 1582 - 1585 (2008/09/17)
(Chemical Equation Presented) A highly convergent total synthesis of bitungolide F leading to the assignment of its absolute stereochemistry is described. The key steps include a Horner-Wadsworth-Emmons olefination to construct the C7-C8 bond, a Wittig reaction to introduce the conjugate E,E-olefinic moiety in the molecule, and finally a ring-closing metathesis reaction to construct the six-membered α,β-unsaturated δ-lactone of the molecule. Modified Evans's syn-aldol reaction, using Crimmins's protocol, was used to install the stereochemistries at the C4 and C5 centers. The stereochemistry at C9 was introduced by means of hydroxy-directed reduction of the C9 keto using Evans's protocol.
Towards EPC-syntheses of the structural class of cochleamycins and macquarimicins. Part 3: EPC-syntheses of the β-keto lactone subunits and first attempts towards the syntheses of the pentacyclic antibiotics of this group
Chrobok,G?ssinger,Grünberger,K?hlig,White,Wuggenig
, p. 8336 - 8350 (2008/02/05)
Practical EPC-syntheses of δ-substituted-β-keto δ-lactones, subunits of the cochleamycins and macquarimicins, are presented. In consequence Tietze's tandem reaction is employed to combine δ-allyl-β-keto δ-lactone with a hydrindene derivative, the second subunit of these acetogenic antibiotics. Model reactions for the final oxidative radical tandem cyclization reveal that the electrophilic radical cyclizes exclusively in exo-trig fashion. However, with the intended precursor of macquarimicin C allylic hydrogen abstraction thwarted the oxidative radical tandem cyclization.
Total synthesis of (-)-pateamine A, a novel immunosuppressive agent from Mycale sp
Pattenden, Gerald,Critcher, Douglas J.,Remuinan, Modesto
, p. 353 - 365 (2007/10/03)
A convergent synthesis of the unique thiazole-containing polyene bis-lactone pateamine A (1) isolated from the marine sponge Mycale sp is described. The synthesis features the ubiquitous Stille sp2-sp 2 coupling reaction to elaborate the E,Z-diene macrolide core 23 and the all-E polyenamine side chain in the natural product. It also highlights the scope for enantiopure sulfinimine intermediates in the synthesis of chiral β-amino ester moieties in complex structures.
A concise and stereoselective synthesis of the A-ring fragment of the gambieric acids
Clark, J. Stephen,Fessard, Thomas C.,Wilson, Claire
, p. 1773 - 1776 (2007/10/03)
Matrix presented. The A-ring fragment of the gambieric acids has been prepared by a short and efficient route. The key 3(2H)-furanone intermediate has been obtained by [2,3] rearrangement of an allylic oxonium ylide generated from intramolecular reaction
A short access to the macrocyclic core of cycloviracin and glucolipsin
Bailliez, Vincent,Figueiredo, Renata M. de,Olesker, Alain,Cleophax, Jeannine
, p. 9151 - 9154 (2007/10/03)
The macrocyclic core of cycloviracin and glucolipsin has been synthesised in ten steps from levoglucosan and (S)-(-)-dimethyl malate. The limited number of steps to obtain this macrolide makes it a valuable procedure for the synthesis of analogues of cycl
Stereochemistry of sphinxolides and reidispongiolides. Asymmetric synthesis of the C17-C22 fragment of reidispongiolide A
Zampella, Angela,Bassarello, Carla,Bifulco, Giuseppe,Gomez-Paloma, Luigi,D'Auria, Maria Valeria
, p. 785 - 790 (2007/10/03)
Five fragments, 2a-4b, embedding all the stereogenic centers of reidispongiolide A (1), have been prepared by a controlled ozonolysis of the natural compound. The absolute stereochemistry of the asymmetric centers of fragment 3, corresponding to the C17-C22 portion of reidispongiolide A, was determined by enantioselective synthesis and application of the advanced Mosher method.
