193416-54-5Relevant academic research and scientific papers
Modular Total Synthesis of iso-Archazolids and Archazologs
Dedenbach, Simon,Menche, Dirk,Rivière, Solenne,Ruiz, Johal,Scheeff, Stephan
, p. 10190 - 10223 (2021/08/16)
Full details on the design, development, and successful implementation of suitable synthetic strategies directed toward the total synthesis of iso-archazolids and archazologs are reported. Both a biomimetic and a multistep total synthesis of iso-archazolid B, the most potent and least abundant archazolid, are described. The bioinspired conversion from archazolid B was realized by a high-yielding 1,8-Diazabicyclo[5.4.0]undec-7-ene catalyzed one-step double-bond shift. A highly stereoselective total synthesis was accomplished in 25 steps, involving a sequence of highly stereoselective aldol reactions, an efficient aldol condensation to forge two elaborate fragments, and a challenging ring-closing metathesis macrocyclization with an unusual Stewart-Grubbs catalyst. These strategies proved to be generally useful and could be successfully implemented for the preparation of three novel iso-archazolids as well as five novel archazologs, lacking the thiazole side chain. A wide variety of further archazolids and archazologs may now be targeted for exploration of the promising anticancer potential of these polyketide macrolides.
An efficient organocatalytic method for highly enantioselective michael addition of malonates to enones catalyzed by readily accessible primary amine-thiourea
Dudzinski, Krzysztof,Pakulska, Anna M.,Kwiatkowski, Piotr
supporting information; experimental part, p. 4222 - 4225 (2012/09/22)
A practical and highly enantioselective Michael addition of malonates to enones catalyzed by simple and readily available bifunctional primary amine-thiourea derived from 1,2-diaminocyclohexane is reported. The addition of weak acids and elevated temperature (ca. 50 °C) improved the efficiency of the Michael reaction. This approach enables the efficient synthesis of 1,5-ketoesters with good yields, excellent enantioselectivities (up to 99% ee), and low loading (0.5-5 mol %) of simple chiral primary amine-thiourea catalysts, and is applicable in multigram scale synthesis.
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.
supporting information; experimental part, 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.
Stereocontrolled total synthesis of (+)-leucascandrolide A
Paterson, Ian,Tudge, Matthew
, p. 343 - 347 (2007/10/03)
Apparently no longer available from its natural source is the potent cytotoxic and antifungal agent leucascandrolide A (1), which was initially isolated from a New Caledonian calcareous sponge. A highly stereocontrolled total synthesis of this structurally unique macrolide commences with a Jacobsen asymmetric hetero Diels-Alder reaction to configure the tetrahydropyran ring. An efficient endgame relies on two Mitsunobu reactions, the first to generate the 18-membered macrolactone and the second to attach the oxazole-bearing side chain.
