149764-51-2Relevant articles and documents
Thiazolium-catalyzed intermolecular Stetter reaction of linear and cyclic alkyl α-diketones
Bortolini, Olga,Fantin, Giancarlo,Fogagnolo, Marco,Giovannini, Pier Paolo,Massi, Alessandro,Pacifico, Salvatore
experimental part, p. 8437 - 8444 (2012/04/10)
An efficient method for the N-heterocyclic carbene (NHC)-catalyzed conjugate addition of acetyl anions to various α,β-unsaturated acceptors (Stetter reaction) has been optimized by using 2,3-butandione (biacetyl) as an alternative surrogate of acetaldehyde. The disclosed procedure proved to be compatible with microwave dielectric heating for reaction time reduction and with the use of different linear α-diketones as acyl anion donors (e.g. 3,4-hexanedione for propionyl anion additions). Moreover, the unprecedented umpolung reactivity of cyclic α-diketones in the atom economic nucleophilic acylation of chalcones is herein presented. Mechanistic aspects of the thiazolium-based catalysis involving linear and cyclic α-diketone substrates are also discussed. The Royal Society of Chemistry 2011.
Ring-opening of tertiary cyclopropanols derived from β-diketones
Li, Le-Zhen,Xiao, Bin,Guo, Qing-Xiang,Xue, Song
, p. 7762 - 7771 (2007/10/03)
The ring-opening reaction of 1,2-disubstituted cyclopropanols, prepared from β-diketones, mediated by Cu(NO3)2, p-TsOH, and NaOH is reported. The Cu(II)-mediated ring-opening of cyclopropanols gave α-methylene-γ-diketones in good yie
Cross-coupling reaction of α-chloroketones and organotin enolates catalyzed by zinc halides for synthesis of γ-diketones
Yasuda, Makoto,Tsuji, Shoki,Shigeyoshi, Yusuke,Baba, Akio
, p. 7440 - 7447 (2007/10/03)
The reaction of tin enolates 1 with α-chloro- or bromoketones 2 gave γ-diketones (1,4-diketones) 3 catalyzed by zinc halides. In contrast to the exclusive formation of 1,4-diketones 3 under catalytic conditions, uncatalyzed reaction of 1 with 2 gave aldol-type products 4 through carbonyl attack. NMR study indicates that the catalyzed reaction includes precondensation between tin enolates and α-haloketones providing an aldol-type species and their rearrangement of the oxoalkyl group with leaving halogen to produce 1,4-diketones. The catalyst, zinc halides, plays an important role in each step. The carbonyl attack for precondensation is accelerated by the catalyst as Lewis acid and the intermediate zincate promotes the rearrangement by releasing oxygen and bonding with halogen. Various types of tin enolates and α-chloro and bromoketones were applied to the zinc-catalyzed cross-coupling. On the other hand, the allylic halides, which have no carbonyl moiety, were inert to the zinc-catalyzed coupling with tin enolates. The copper halides showed high catalytic activity for the coupling between tin enolates 1 and organic halides 7 to give γ,δ-unsaturated ketones 8 and/or 9. The reaction with even chlorides proceeded effectively by the catalytic system.
Facile Control of Regioselectivity in the Reaction of Tin Enolates with α-Halogeno Carbonyls by Additives
Yasuda, Makoto,Oh-hata, Tatsuhiro,Shibata, Ikuya,Baba, Akio,Matsuda, Haruo
, p. 859 - 866 (2007/10/02)
Tin enolates 1 reacted with α-halogeno ketones 2 and esters 10 to give a variety of 1,4-diketones 3 and γ-keto esters 11, respectively, in the presence of appropriate additives such as hexamethylphosphoric triamide (HMPT), tributylphosphine oxide and tetrabutylammonium bromide, while complexation of these additives with tributyltin bromide allowed catalytic production of β-keto oxiranes 4 instead of 3.The reaction mechanism for the preparation of 1,4-diketone 3 is discussed.
