Divergent Synthesis of L-Sugars and L-Iminosugars from D-Sugars

• Published in: Chemistry : a European journal Vol. 12; no. 22; pp. 5868 - 5877
• Main Authors: Takahashi, Hideyo, Shida, Tomomi, Hitomi, Yuko, Iwai, Yoshinori, Miyama, Namisa, Nishiyama, Kazusa, Sawada, Daisuke, Ikegami, Shiro
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 24.07.2006; WILEY‐VCH Verlag
• Subjects: azasugars; Carbohydrate Conformation; carbohydrates; Carbohydrates - chemical synthesis; Carbohydrates - chemistry; Cyclization; Iduronic Acid - chemical synthesis; Imino Sugars - chemical synthesis; lactams; lactones; Lactones - chemistry; Mitsunobu reaction; Siloxanes - chemistry; Styrenes - chemistry
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200600268

An efficient divergent synthesis of L‐sugars and L‐iminosugars from D‐sugars is described. The important intermediate, δ‐hydroxyalkoxamate, prepared from D‐glucono‐/galactono‐1,5‐lactone, was cyclized under Mitsunobu conditions to give the O‐cyclized oxime compound and the N‐cyclized lactam compound as mixtures. A more detailed investigation revealed that the appropriate protecting groups and solvents controlled the specificity for the O‐/N‐cyclization of the δ‐hydroxyalkoxamate. Suitable protection at the 6‐position of δ‐hydroxyalkoxamate, derived from D‐glucono‐1,5‐lactone, afforded the corresponding O‐alkylation product alone. Thus we succeeded in applying this to the total synthesis of L‐iduronic acid. In contrast, with both TBDMS as the protecting group and RCN as the solvent the efficient conversion of D‐glucono/galactono‐1,5‐lactone into the corresponding L‐iminosugars (L‐idonolactam and L‐altronolactam) was achieved. Sweeten your synthesis! An efficient divergent synthesis of L‐sugars and L‐iminosugars from D‐sugars is described. The important intermediate, δ‐hydroxyalkoxamate, prepared from D‐glucono‐/galactono‐1,5‐lactone, was cyclized under Mitsunobu conditions to give the O‐cyclized oxime and the N‐cyclized lactam compounds as mixtures.