89036-08-8Relevant articles and documents
A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones
Hosono, Kazumi,Kodama, Shintaro,Nomoto, Akihiro,Ochi, Takanori,Ogawa, Akiya,Tabuchi, Akihiro,Yamamoto, Yuki,Yamazaki, Kento
supporting information, p. 2906 - 2914 (2022/01/12)
A simple and efficient method for α-brominating lactones that affords α-bromolactones under mild conditions using tetraalkylammonium hydroxide (R4N) as a base was developed. Lactones are ring-opened with Br2 and a substoichiometric amount of PBr3, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H2O/CHCl3) containing R4N afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates.
An Useful Synthetic Method for 3-Substituted δ-Lactones. Synthesis of (+/-)-Secocrispiolide
Kato, Michiharu,Ouchi, Akihiko,Yoshikoshi, Akira
, p. 1479 - 1486 (2007/10/02)
2-Phenylthio-2-penten-5-olide (1) acted as a reactive Michael acceptor toward some typical carbon nucleophiles to give 3-substituted 2-phenylthio-5-pentanolides (2) which were convertible both to 3-substituted 5-pentanolides by reductive desulfurization and to 3-substituted 2-penten-5-olides by sulfenic acid syn elimination of the sulfoxides 4 derived from 2.The Pummerer rearrangement of 4 provided 3-substituted 2-phenylthio-2-penten-5-olides and/or 2-hydroxy-2-penten-5-olides. (+/-)-Secocrispiolide was synthesized via the adduct obtained by the Michael reaction of 1 with the Grignard reagent prepared from 2,6-dimethylbenzyl bromide and magnesium.
2-(PHENYLTHIO)-2-PENTEN-5-OLIDE, A NEW BUILDING BLOCK FOR THE SYNTHESIS OF 3-SUBSTITUTED γ-LACTONES
Kato, Michiharu,Ouchi, Akihiko,Yoshikoshi, Akira
, p. 1511 - 1514 (2007/10/02)
2-(Phenylthio)-2-penten-5-olide, readily accessible from γ-valerolactone, showed high electrophilic reactivities toward some typical carbon nucleophiles to give 3-substituted 2-(phenylthio)pentanolides, which were convertible to a variety of 3-substituted
