title: Lewis acid catalyzed cyclization of glycals/2-deoxy-D-ribose with arylamines: additional findings on product structure and reaction diastereoselectivity.
abstract: The cyclization reactions of arylamines with 2-deoxy-D-ribose or glycals were reinvestigated in the current report. In the montmorillonite KSF- or InCl(3)-initiated reactions of 2-deoxy-D-ribose with arylamines, a pair of diastereomeric tetrahydro-2H-pyran-fused tetrahydroquinolines was obtained in a nearly 1:1 ratio where the structure of one diastereomer was incorrectly assigned in the literature. Meanwhile, the diastereoselectivity in InBr(3)-catalyzed cyclization of glycals with arylamines was also incorrectly reported previously. It was found that high diastereomeric selectivity was achieved only when a C5-substituted glycal was used; otherwise, a pair of diastereomers was obtained in moderate yield with 1:1 diastereomeric ratio. Furthermore, tetrahydrofuran-fused tetrahydroquinolines 5b and 5b' were also prepared successfully by using TBDPS-protected ribose as the glycal precursor and montmorillonite KSF as the activator.
authors.affiliation: Synthetic Organic & Medicinal Chemistry Laboratory, Shanghai Institute of Materia Medica, Shanghai 201203, China.
authors.forename: Chengtang
authors.initials: C
authors.lastname: Du
authors.forename: Fulong
authors.initials: F
authors.lastname: Li
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Zhang
authors.forename: Wenxiang
authors.initials: W
authors.lastname: Hu
authors.forename: Qizheng
authors.initials: Q
authors.lastname: Yao
authors.forename: Ao
authors.initials: A
authors.lastname: Zhang
mesh_terms: D000588:Amines / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D005663:Furans / Q000737:chemistry; D058116:Lewis Acids / Q000737:chemistry*; D015394:Molecular Structure; D011804:Quinolines / Q000737:chemistry; D012266:Ribose / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000588:Amines; D005663:Furans; D058116:Lewis Acids; D011804:Quinolines; D001546:Bentonite; D012266:Ribose