title: Synthetic studies on (+)-biotin, part 15: A chiral squaramide-mediated enantioselective alcoholysis approach toward the total synthesis of (+)-biotin.
abstract: An efficient stereocontrolled total synthesis of (+)-biotin (1) has been achieved via the intermediacy of Roche's lactone 5 starting from cis-1,3-dibenzyl-2-imidazole-4,5-dicarboxylic acid (2). The bifunctional cinchona alkaloid-derived squaramide-promoted enantioselective alcoholysis was utilizing as a tool for the construction of two contiguous stereocenters of C-3a and C-6a in biotin molecular with excellent enantioselectivity. In addition, the 4-carboxybutyl side chain was assembled by first using C4+C1 approach via a novel tricyclic thiophanium salt intermediate.
authors.affiliation: Fudan-DSM Joint Laboratory for Synthetic Method and Chiral Technology, Department of Chemistry, Fudan University.
authors.forename: Xu-Xiang
authors.initials: XX
authors.lastname: Chen
authors.forename: Fei
authors.initials: F
authors.lastname: Xiong
authors.forename: Han
authors.initials: H
authors.lastname: Fu
authors.forename: Zhi-Qian
authors.initials: ZQ
authors.lastname: Liu
authors.forename: Fen-Er
authors.initials: FE
authors.lastname: Chen
mesh_terms: D000577:Amides / Q000737:chemistry*; D001710:Biotin / Q000138:chemical synthesis* / Q000737:chemistry; D003998:Dicarboxylic Acids / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000577:Amides; D003998:Dicarboxylic Acids; D001710:Biotin