Intramolecular transformations of derivatives of the Michael adduct of levoglucosenone and 2-(ethoxycarbonyl)cyclododecanone. 2. Ethylene ketal and its bromination—dehydrobromination products

Ethylene ketal of the Michael adduct of levoglucosenone and 2-(ethoxycarbonyl)cyclo-dodecanone brominated with the system Br 2 —CCl 4 in CHCl 3 gave three types of products, namely, mono- and dibromo derivatives, as well as deprotected bromo diketone. The bromination occurred in the levoglucosenone...

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Bibliographic Details
Published in:Russian chemical bulletin 2023-10, Vol.72 (10), p.2418-2424
Main Authors: Faizullina, L. Kh, Galimova, Yu. S., Salikhov, Sh. M., Valeev, F. A.
Format: Article
Language:English
Subjects:
Bromination
Chemistry
Chemistry and Materials Science
Chemistry/Food Science
Chloroform
Cyclopropane
Diketones
Ethylene
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Inorganic Chemistry
Organic Chemistry
Sodium bicarbonate
Stereoselectivity
Tetrahydrofuran
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Summary:Ethylene ketal of the Michael adduct of levoglucosenone and 2-(ethoxycarbonyl)cyclo-dodecanone brominated with the system Br 2 —CCl 4 in CHCl 3 gave three types of products, namely, mono- and dibromo derivatives, as well as deprotected bromo diketone. The bromination occurred in the levoglucosenone moiety and in the cyclododecanone fragment, with the ketal protection being partially removed. Reductive debromination of difficult-to-separate di- and monobromo derivatives under the action of Zn—Bu 4 NI in EtOAc—EtOH and ultrasound led to the opening of the protective group dioxolane ring to give the corresponding enol ether. Treatment of the mixture of di- and monobromo derivatives with the system NaOH—EtOH or NaHCO 3 —DMSO triggered a stereoselective intramolecular cyclization to result in the cyclopropane and tetrahydrofuran derivatives, respectively.
ISSN:1066-5285
1573-9171
DOI:10.1007/s11172-023-4042-4