83889-77-4Relevant articles and documents
Chiral squaramide-mediated methanolytic desymmetrization of prochiral cyclic anhydride: A convenient approach for synthesizing roche lactone
Ding, Liang-Qian,Hong, Dan-Feng,Liu, Wen-Guang,Ma, Hui,Tan, Qing-Gang,Wang, Shi-Heng,Wu, Si-Qin,Xiong, Fei
, p. 429 - 432 (2018/09/25)
The main objective of this report was to develop an improved process for the asymmetric synthesis of (3aS, 6aR)-lactone 1, which is the key chiral intermediate of (+)-biotin. This practical and efficient process includes a novel chiral squaramide alkamine derivatives 5 mediated methanolytic desymmetrization of prochiral cyclic anhydride 3 to produce the enantiomerically enriched precursor of Roche lactone.
Highly enantioselective methanolysis of meso-cyclic anhydride mediated by bifunctional thiourea cinchona alkaloid derivatives: Access to asymmetric total synthesis of (+)-biotin
Xiong, Fei,Xiong, Fang-Jun,Chen, Wen-Xue,Jia, Hui-Qing,Chen, Fen-Er
, p. 1078 - 1082 (2013/10/21)
An enantioselective asymmetric total synthesis of (+)-biotin (1) via the Hoffmann-Roche lactone-thiolactone strategy has been accomplished from commercially available cis-1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid (2). Strategic transformations include a cinchona alkaloid-based bifunctional thiourea mediated methanolytic desymmetrization of prochiral cyclic anhydride 3 to produce the enantiomerically enriched precursor of Roche lactone 5 and an improved introduction of the 4-carboxybutyl side chain at C-4 position of Roche thiolactone 6 via Grignard reaction.
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.