Halogen addition to some 1-C-substituted pyranoid glycals

• Published in: Carbohydrate research Vol. 504; pp. 108292 - 108302
• Main Authors: Homolya, Levente, Juhász, László, Somsák, László
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.06.2021; Elsevier
• Subjects: 1-C-Substituted glycal; Biochemistry & Molecular Biology; Chemistry; Chemistry, Applied; Chemistry, Organic; Glycosides - chemical synthesis; Glycosides - chemistry; Glycosyl halide; Glycosylation; Halogen addition; Halogenation; Halogens - chemistry; Life Sciences & Biomedicine; Molecular Structure; Physical Sciences; Pyrans - chemical synthesis; Pyrans - chemistry; Science & Technology; Glycosylation; 1-C-Substituted glycal; Glycosyl halide; Halogen addition; BIOLOGICAL EVALUATION; GANGLIOSIDES; RADICALS; INHIBITORS; DERIVATIVES; CYANIDES; N-ACETYLNEURAMINIC ACID; TRANSFORMATIONS
• ISSN: 0008-6215; 1873-426X; 1873-426X
• DOI: 10.1016/j.carres.2021.108292

Addition of bromine and chlorine to O-peracylated 1-CN-, COOMe- and CONH2-substituted glycals was studied under ionic and radical conditions. The main or exclusive products were the corresponding 2,3-trans-diaxial (3-bromo-3-deoxy-α-d-heptopyranosylbromide)onic acid derivatives. Bromination of the O-peracetylated d-lyxo-hept-2-enopyranosononitrile and all chlorinations proved selective towards the 2-axial-3-equatorial (3-halogeno-3-deoxy-α-d-heptopyranosylhalide)onic acid derivatives. Silver triflate promoted glycosylation of methanol was successful with each 2,3-trans-diaxial (3-bromo-3-deoxy-α-d-heptopyranosylbromide)onic acid derivative, however, several attempted nucleophilic substitution and elimination reactions gave the parent glycal only. [Display omitted] •Bromine and chlorine addition to 1-CN, -COOMe, –CONH2-substituted pyranoid glycals.•Preferred formation of 2,3-trans-diaxial (3-bromo-3-deoxy-α-D-heptopyranosylbromide)onic acid derivatives.•Preferred formation of 2-axial-3-equatorial (3-chloro-3-deoxy-α-D-heptopyranosylchloride)onic acid derivatives.