180592-86-3Relevant academic research and scientific papers
Total Synthesis of the Proposed Structure of Maltepolide C
Rao, K. Nageswara,Kanakaraju,Kunwar,Ghosh, Subhash
, p. 4092 - 4095 (2016)
The first total synthesis of the proposed structure of cytotoxic macrolide maltepolide C has been achieved via an E-selective intramolecular Heck cyclization as a key step. Other key features of the synthesis are Z-selective Wittig olefination, Sharpless asymmetric dihydroxylation followed by Williamson-type cyclo-etherification, Brown asymmetric allylation, and Noyori reduction of an alkynone. Detailed NMR study confirms the structure and stereochemistry of the synthetic maltepolide C unambiguously. However, the deviation of the spectra of the synthetic maltepolide C from those of the natural maltepolide C indicates a possible error in the original structural assignment.
Synthetic Studies toward the C32-C46 Segment of Hemicalide. Assignment of the Relative Configuration of the C36-C42 Subunit
Specklin, Simon,Boissonnat, Guillaume,Lecourt, Camille,Sorin, Geoffroy,Lannou, Marie-Isabelle,Ardisson, Janick,Sautel, Fran?ois,Massiot, Georges,Meyer, Christophe,Cossy, Janine
, p. 2446 - 2449 (2015/05/27)
The synthesis of five diastereomeric model compounds incorporating the C32-C46 segment of the antitumor marine natural product hemicalide has been achieved through a convergent approach relying on the 1,4-addition of an alkenyl boronate to an α,β-unsaturated δ-lactone followed by α-hydroxylation of an enolate and a Julia-Kocienski olefination. Comparison of the 1H and 13C NMR data of the model compounds with those of hemicalide enabled the assignment of the relative configuration of the C36-C42 subunit. (Chemical Equation Presented).
Total synthesis and evaluation of phostriecin and key structural analogues
Burke, Christopher P.,Swingle, Mark R.,Honkanen, Richard E.,Boger, Dale L.
scheme or table, p. 7505 - 7513 (2011/02/23)
Full details of the total synthesis of phostriecin (2), the assignment of its relative and absolute stereochemistry, and the resultant structural reassignment of the natural product previously represented as sultriecin (1), a phosphate versus sulfate mono
Total synthesis, assignment of the relative and absolute stereochemistry, and structural reassignment of phostriecin (aka Sultriecin).
Burke, Christopher P.,Haq, Nadia,Boger, Dale L.
supporting information; experimental part, p. 2157 - 2159 (2010/05/11)
A total synthesis of phostriecin (2), previously known as sultriecin (1), its structural reassignment as a phosphate versus sulfate monoester, and the assignment of its relative and absolute stereochemistry are disclosed herein. Key elements of the work, which provided first the originally assigned sulfate monoester 1 and then the reassigned and renamed phosphate monoester 2, relied on diagnostic (1)H NMR spectroscopic properties of the natural product for the assignment of relative and absolute stereochemistry as well as the subsequent structural reassignment, and a convergent asymmetric total synthesis to provide the unequivocal authentic materials. Key steps of the synthetic approach include a Brown allylation for diastereoselective introduction of the C9 stereochemistry, an asymmetric CBS reduction to establish the lactone C5-stereochemistry, diastereoselective oxidative ring expansion of an alpha-hydroxyfuran to access the pyran lactone precursor, and single-step installation of the sensitive Z,Z,E-triene unit through a chelation-controlled cuprate addition with installation of the C11 stereochemistry. The approach allows ready access to analogues that can now be used to probe important structural features required for protein phosphatase 2A inhibition, the mechanism of action defined herein.
Total Synthesis of Swinholide A, Preswinholide A, and Hemiswinholide A
Nicolaou, K. C.,Patron, A. P.,Ajito, K.,Richter, P. K.,Khatuya, H.,et al.
, p. 847 - 868 (2007/10/03)
The total synthesis of swinholide A (1) has been accomplished via key intermediate aldehyde 12 (Fig. 3), whose construction started from L-rhamnose (18), epoxide 21, and phenylsulfone orthoester 22, and proceeded through an Enders asymmetric alkylation (16 + 17 -> 15), a Ghosez cyclization (21 + 22 -> 20), and a Corey-Sharpless coupling reaction (13 + 14 -> 12).Elaboration of compound 12 along slightly different pathways culminated in the synthesis of carboxylic acid 10 and hydroxy compound 11, whose union by an esterification reaction, followed by ring closure of the subsequently derived hydroxy acid under Yamaguchi conditions, led to swinholide A (1) upon deprotection.The chemistry developed also allowed the total synthesis of preswinholide A methyl ester (7), preswinholide A (8), and hemiswinholide A (78).Keywords: natural products; swinholide A; total syntheses
