Beneficial effect of internal hydrogen bonding interactions on the beta-fragmentation of primary alkoxyl radicals. Two-step conversion of D-xylo- and D-ribofuranoses into L-threose and D-erythrose, respectively.
Primary alkoxyl free radicals were generated from their readily synthesized N-phthalimido derivatives under reductive conditions. Primary alkoxyl radicals derived from their corresponding xylo- and ribofuranose derivatives underwent, exclusively, an unusual beta-fragmentation affording L-threose and D-erythrose derivatives, respectively. This occurs because the alkoxyl radical is capable of achieving an internal hydrogen-bonding interaction leading to a stable six-membered ring intramolecular hydrogen-bonded structure. When the hydroxyl group is protected, the beta-fragmentation pathway is prevented and the hydrogen atom transfer (HAT) pathway occurs. Computational studies provided strong support for the experimental observations.
Hernandez-García
Luís
L
Centro de Investigación de la Facultad de Ciencias Químicas, BUAP, 14 Sur Esq. San Claudio, Col. San Manuel, 72570, Puebla, México.
Quintero
Leticia
L
Sánchez
Mario
M
Sartillo-Piscil
Fernando
F
D000438:Alcohols / Q000737:chemistry*; D005663:Furans / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008958:Models, Molecular; D015394:Molecular Structure; D012015:Reference Standards; D013237:Stereoisomerism; D013780:Tetroses / Q000138:chemical synthesis* / Q000737:chemistry
D000438:Alcohols; D005663:Furans; D013780:Tetroses; C059688:alkoxyl radical; C073321:erythrose