title: Asymmetric synthesis of α-amino-1,3-dithianes via chiral N-phosphonyl imine-based Umpolung reaction without using chromatography and recrystallization.
abstract: A series of α-amino-1,3-dithianes have been synthesized via the asymmetric Umpolung reaction of 2-lithio-1,3-dithianes with chiral N-phosphonyl imines in good chemical yields (up to 82%) and good to excellent diastereoselectivities (>99:1). The manner by which chiral N-phosphonyl imines are slowly added into the solution of 2-lithio-1,3-dithiane was found to be crucial for achieving excellent diastereoselectivity. The current synthesis was proven to follow the GAP chemistry (group-assistant-purification chemistry) process, which avoids traditional purification techniques of chromatography or recrystallization, i.e., the pure chiral α-amino-1,3-dithianes attached with the chiral N-phosphonyl group were readily obtained by washing the solid crude products with hexane or a mixture of hexane-ethyl acetate.
authors.affiliation: Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States.
authors.forename: Padmanabha V
authors.initials: PV
authors.lastname: Kattamuri
authors.forename: Teng
authors.initials: T
authors.lastname: Ai
authors.forename: Suresh
authors.initials: S
authors.lastname: Pindi
authors.forename: Yinwei
authors.initials: Y
authors.lastname: Sun
authors.forename: Peng
authors.initials: P
authors.lastname: Gu
authors.forename: Min
authors.initials: M
authors.lastname: Shi
authors.forename: Guigen
authors.initials: G
authors.lastname: Li
mesh_terms: D000085:Acetates / Q000737:chemistry; D000588:Amines / Q000737:chemistry*; D055772:Green Chemistry Technology; D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D006586:Hexanes / Q000737:chemistry; D007097:Imines / Q000737:chemistry; D055601:Organic Chemistry Phenomena; D013237:Stereoisomerism
chemical_list: D000085:Acetates; D000588:Amines; D006571:Heterocyclic Compounds; D006586:Hexanes; D007097:Imines; C012947:1,3-dithiane; C007650:ethyl acetate