title: Fragmentation of carbohydrate anomeric alkoxy radicals: a new synthesis of chiral 1-halo-1-iodo alditols.
abstract: Treatment of 1,2-fluorohydrins, 1,2-chlorohydrins, 1,2-bromohydrins, and 1,2-iodohydrins of the D-gluco, D-galacto, D-lacto, L-rhamno, D-allo, L-arabino, 3-deoxy-D-gluco, and 3,4-dideoxy-D-gluco families of carbohydrates with the (diacetoxyiodo)benzene/iodine system afforded 1-fluoro-1-iodo, 1-chloro-1-iodo, 1-bromo-1-iodo, and 1,1-diiodo alditols, respectively, in excellent yields. The reaction was achieved by radical fragmentation of the C1bond;C2 bond, triggered by the initially formed anomeric alkoxy radical, and subsequent trapping of the C2-radical by iodine atoms. This methodology is compatible with the stability of the protective groups most frequently used in carbohydrate chemistry. The potential utility of these 1-halo-1-iodo alditols as chiral synthons was evaluated by their transformation into alk-1-enyl iodides and in the Takai E-olefination reaction.
authors.affiliation: Instituto de Productos Naturales y Agrobiología del C.S.I.C. Carretera de La Esperanza 3, 38206 La Laguna, Tenerife, Spain.
authors.forename: Concepción C
authors.initials: CC
authors.lastname: González
authors.forename: Alan R
authors.initials: AR
authors.lastname: Kennedy
authors.forename: Elisa I
authors.initials: EI
authors.lastname: León
authors.forename: Concepción
authors.initials: C
authors.lastname: Riesco-Fagundo
authors.forename: Ernesto
authors.initials: E
authors.lastname: Suárez