Tetrahedron: Asymmetry

An improved asymmetric total synthesis of (+)-biotin via the enantioselective desymmetrization of a meso-cyclic anhydride mediated by cinchona alkaloid-based …

F Xiong, XX Chen, FE Chen

Index: Xiong, Fei; Chen, Xu-Xiang; Chen, Fen-Er Tetrahedron Asymmetry, 2010 , vol. 21, # 6 p. 665 - 669

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Citation Number: 22

Abstract

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 ...