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31.
32.
A stereoselective total synthesis of xyolide, a naturally occurring bioactive nonenolide, has been accomplished. The acid fragment of the molecule has been prepared from D ‐mannitol and the alcohol fragment from (2Z)‐but‐2‐ene‐1,4‐diol. The synthesis involves the coupling of these two fragments using the Yamaguchi esterification protocol, followed by intramolecular ring‐closing methathesis. The diastereoisomeric alcohol fragment has also been utilized in this synthesis by employing the Mitsunobu esterification. 相似文献
33.
The stereoselective total synthesis of decytospolides A and B, two naturally occurring pyran derivatives, has been achieved using D ‐mannitol as the starting material. The intramolecular oxa‐Michael reaction has been employed to construct the tetrahydropyran ring of the molecules and Weinreb amide formation to generate their side chain with a keto function. 相似文献
34.
Stereoselective Synthesis of the Non‐Lactonic Portion of (Z)‐Cryptofolione and Approaches towards Its Conversion to (Z)‐Cryptofolione
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The stereoselective synthesis of the non‐lactonic part of the natural G2 checkpoint inhibitor, (Z)‐cryptofolione, has been accomplished. Butane‐1,4‐diol was used as the starting material, and the stereogenic centers were generated through L ‐proline‐catalyzed α‐aminoxylation and Maruoka asymmetric allylation. We attempted to convert this non‐lactonic moiety to (Z)‐cryptofolione via olefin cross‐metathesis reaction, but by this approach another naturally occurring lactonic compound, goniothalamin, was obtained. 相似文献
35.
Stereoselective total synthesis of ophiocerin C has been accomplished through two different approaches starting separately from acetaldehyde and from (R)‐propylene oxide, and Sharpless asymmetric dihydroxylation has been employed as the key step in both approaches. 相似文献
36.
Dinda J Liatard S Chauvin J Jouvenot D Loiseau F 《Dalton transactions (Cambridge, England : 2003)》2011,40(14):3683-3688
This work describes the synthesis and characterization of two new bis-terdentate Ru(II) complexes. Compound 1 is a homoleptic complex containing two CNC N-heterocyclic carbene (NHC) based ligands, whereas compound 2 bears one CNC ligand and an ancillary terpyridine ligand. The redox and photophysical properties of both compounds have been investigated and their X-ray crystal structures determined. Complex 1 displays a close-to-perfect octahedral coordination geometry and is not luminescent at room temperature while complex 2 features room temperature and 77 K luminescence despite its partially distorted geometry. The presence of the NHC moieties brings a significant amount of electronic density to the metal centre therefore lowering its oxidation potential with respect to that of analogous polypyridyl complexes. 相似文献
37.
A compilation of new naturally occurring iridoids and secoiridoids including their glycosides, esters, aglycones, derivatives and dimers reported during mid 2008-2010 is provided with available physical and spectral data: mp, [α](D), UV, IR, circular dichroism (CD), (1)H- and (13)C-NMR as well as natural source with family and references. The important bioactivity of new and known iridoids and secoiridoids reported during this period is also highlighted. 相似文献
38.
Biswanath Das Yallamalla Srinivas Chithaluri Sudhakar Parigi Raghavendar Reddy 《Helvetica chimica acta》2011,94(7):1290-1295
The stereoselective synthesis of the naturally occurring dihydropyranone rugulactone has been accomplished starting from 3‐phenylpropan‐1‐ol employing Maruoka allylation and ring‐closing metathesis as the key steps. 相似文献
39.
Biswanath Das Maddeboina Krishnaiah Ponnaboina Thirupathi Keetha Laxminarayana 《Tetrahedron letters》2007,48(24):4263-4265
A catalyst-free regio- and stereoselective ring-opening of epoxides with phenoxides has been carried out efficiently using polyethylene glycol as the reaction medium to form the corresponding β-aryloxyalcohols in high yields at room temperature. 相似文献
40.