Intramolecular transformations of derivatives of the Michael adduct of levoglucosenone and 2-(ethoxycarbonyl)cyclododecanone. 1. Regioselective cleavage of the Cα—C(O) bonds

• Published in: Russian chemical bulletin 2023-10, Vol.72 (10), p.2411-2417
• Main Authors: Faizullina, L. Kh, Galimova, Yu. S., Salikhov, Sh. M., Valeev, F. A.
• Format: Article
• Language: English
• Subjects: Alkylation; Carbohydrates; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Cleavage; Decarboxylation; Full Articles; Hydrogen peroxide; Inorganic Chemistry; Organic Chemistry
• ISSN: 1066-5285; 1573-9171
• DOI: 10.1007/s11172-023-4041-5

2,3,3-Trimethoxyhexadecahydropyrano[2,3 -c ][1]oxacyclohexadecene-5,16-dione, used in the synthesis of a 16-membered macrolide, was obtained using an approach alternative to the previously published two-step procedure, which consisted in the decarboxylation of the Michael adduct of levoglucosenone and 2-(ethoxycarbonyl)cyclododecan-one under the action of Bu t OK in Bu t OH. A regiospecific Baeyer—Villiger reaction was discovered to proceed under the action of H 2 O 2 in the presence of p -TsOH, which was accompanied by the dioxolane protective group removal and the C(4)(O)—C(5) bond cleavage with the formation of a γ-lactone ring. Treatment with Bu t OK resulted in the fragmentation of the difficult-to-enolize 2-(ethoxycarbonyl)cyclododecanone fragment of the molecule with the C(1′)—C(2′)(O) bond cleavage and the formation of a linear substituent at the carbohydrate residue with a terminal carboxy group. The latter transformation represented an alternative route for the preparation of 4-alkylated levoglucosenone derivatives substituted at the keto group.