Bromocyclization of Alkenoic Thioester and Access to Functionalized Sulfur-Heterocycles
Rinako Saegusa, Takashi Fujihara, Hiroki Shigehisa*
*Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi Nishitokyo,
Tokyo 202-8585, Japan, Email: cgehisa
musashino-u.ac.jp
R. Saegusa, T. Fujihara, H. Shigehisa, Org. Lett., 2023, 25, 8777-8781.
DOI: 10.1021/acs.orglett.3c02953
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Abstract
A bromocyclization of alkenoic thioesters in the presence of N-bromoacetamide (NBA) provides cyclic bromosulfides. The resulting 5-exo products are labile and can be used in various nucleophilic substitution reactions.
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General procedure of bromocyclization
To a solution of alkenoic thioester (0.100 mmol) in dichloromethane (1.0 mL) was added N-bromoacetamide (15.2 mg, 0.110 mmol) at 0°C. After being stirred for 20 hours at the same temperature, the reaction mixture was quenched by the addition of saturated sodium thiosulfate solution. The water layer was extracted with dichloromethane. The organic portion was washed with brine, dried over anhydrous sodium sulfate, and concentrated in vacuo. The residue was purified by flash column chromatography to afford the desired product.
Key Words
tetrahydrothiophenes, N-bromoacetamide
ID: J54-Y2023
