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Fragmentation of Carbohydrate Anomeric Alkoxy Radicals: A New Synthesis of Chiral 1‐Halo‐1‐iodo Alditols
Author(s) -
González Concepción C.,
Kennedy Alan R.,
León Elisa I.,
RiescoFagundo Concepción,
Suárez Ernesto
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200305294
Subject(s) - anomer , fragmentation (computing) , alkoxy group , radical , halo , chemistry , carbohydrate , organic chemistry , medicinal chemistry , photochemistry , physics , astrophysics , computer science , alkyl , operating system , galaxy
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 ‐ arabin o, 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 C1C2 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.