1055329-67-3Relevant academic research and scientific papers
An improved asymmetric total synthesis of (+)-biotin via the enantioselective desymmetrization of a meso-cyclic anhydride mediated by cinchona alkaloid-based sulfonamide
Xiong, Fei,Chen, Xu-Xiang,Chen, Fen-Er
experimental part, p. 665 - 669 (2010/07/17)
The highly enantioselective total synthesis of (+)-biotin 1 via the Hoffmann-Roche lactone-thiolactone strategy has been achieved starting from cis-1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid 2 with an overall yield of 35%. Two contiguous stereogenic centers at C-3a and C-6a were established through a rapid cinchona alkaloid-based sulfonamide-mediated enantioselective alcoholysis of meso-cyclic anhydride 3 to afford (4S,5R)-cinnamyl hemiester 4h, the direct precursor to (3aS,6aR)-lactone 5 with high enantioselectivity. A one-pot installation of the 4-carboxybutyl side chain was accomplished by a Fukuyama coupling reaction of (3aS,6aR)-thiolactone 6 with the organozinc reagent prepared from ethyl 5-bromopentanoate.
A novel cost-effective thiourea bifunctional organocatalyst for highly enantioselective alcoholysis of meso-cyclic anhydrides: Enhanced enantioselectivity by configuration inversion
Wang, Su-Xi,Chen, Fen-Er
supporting information; experimental part, p. 547 - 552 (2009/10/25)
A novel inexpensive thiourea bifunctional organocatalyst which can promote the highly enantioselective (up to 95% ee) alcoholysis of mesocyclic anhydrides has been developed. Computational studies on the catalytic process as well as a synthetic application of this new catalyst are also presented.
A PREPARATION METHOD OF (4S,5R)-SEMIESTER
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Page/Page column 4-5, (2009/12/28)
A preparation method of (4S,5R)-semiester in which cycloanhydride conducts enantioselective ring-opening with alcohol in the presence of 9-epiquininurea. With this method, (4S,5R)-semiester is prepared at room temperature with high yield and high stereose
Total synthesis of (+)-biotin via a quinine-mediated asymmetric alcoholysis of meso-cyclic anhydride strategy
Huang, Jian,Xiong, Fei,Chen, Fen-Er
, p. 1435 - 1442 (2008/12/20)
A concise asymmetric total synthesis of (+)-biotin 1 has been accomplished in which the absolute stereochemistry of C3a, C6a of 1 was established by utilizing an efficient and practical quinine-mediated asymmetric alcoholysis of meso-cyclic anhydride 2 in a single step, the C4 stereochemistry was installed by a direct stereoselective ionic hydrogenation of the thiolactol 7.
