22780-11-6Relevant academic research and scientific papers
Chiral Silver Alkoxide Catalyzed Asymmetric Aldol Reaction of Alkenyl Esters with Isatins
Yanagisawa, Akira,Kawada, Aiko
supporting information, p. 1246 - 1252 (2021/05/05)
A catalytic enantioselective aldol reaction of alkenyl esters with isatins was achieved using a DM-BINAP·AgOTf complex as the chiral precatalyst and N, N -diisopropylethylamine as the base precatalyst in the presence of methanol or 2,2,2-trifluoroethanol.
Asymmetric Aldol Reaction of Alkenyl Esters with α-Keto Esters Catalyzed by Chiral Tin Alkoxides
Takagi, Kotaro,Uchiyama, Chika,Yanagisawa, Akira
supporting information, p. 2085 - 2089 (2021/12/01)
A catalytic enantioselective aldol reaction of alkenyl esters with α-keto esters was achieved by using an (R)-BINOL-derived chiral tin dibromide possessing 4-t-butylphenyl groups at the 3- and 3′-positions as a chiral precatalyst in the presence of sodium methoxide and methanol. Optically active aldol products possessing a chiral tertiary carbon were diastereoselectively obtained with up to 92% ee and moderate to high yields, not only from cyclic alkenyl esters, but also from acyclic ones under the influence of the chiral tin methoxide generated in situ.
Catalytic enantioselective mannich-type reaction via a chiral silver enolate
Yanagisawa, Akira,Lin, Yuqin,Miyake, Ryoji,Yoshida, Kazuhiro
supporting information, p. 86 - 89 (2014/01/23)
A catalytic asymmetric Mannich-type reaction of alkenyl trichloroacetates with aldimines was achieved using SEGPHOS·AgOTf as the chiral precatalyst and N,N-diisopropylethylamine as the base precatalyst in the presence of 2,2,2-trifluoroethanol. Optically
Asymmetric aldol reaction catalyzed by a chiral phosphine-silver complex
Yanagisawa, Akira,Miyake, Ryoji,Yoshida, Kazuhiro
supporting information, p. 4248 - 4253 (2014/07/21)
A catalytic asymmetric aldol reaction of alkenyl trihaloacetates or a γ,δ-unsaturated δ-lactone with aldehydes or an α-keto ester was achieved by using a 2,2′-bis(diphenylphosphino)-1,1′- binaphthyl·silver trifluoromethanesulfonate complex as the chiral p
Practical synthesis of gem-difluorides from cyclohexanone: Synthesis of gem-bistrifluoroacetates and their reactions with fluoride nucleophiles
Tojo, Masahiro,Fukuoka, Shinsuke,Tsukube, Hiroshi
experimental part, p. 29 - 35 (2010/03/30)
Formation of ketone acylals bearing trihaloacetoxy groups and their nucleophilic geminal disubstitution by fluoride ions were investigated. Cyclohexanone reacted with trifluoroacetic anhydride without catalyst to give gem-bistrifluoroacetates via a concerted bimolecular reaction. Treatment with hydrogen fluoride under mild conditions efficiently yielded the corresponding gem-difluorides. In this reaction process, trifluoroacetic acid was recovered and converted to trifluoroacetic anhydride using P2O5. Since gem-difluorides were derived from ketones, HF and P2O5, this constitutes a practical synthesis of gem-difluorides.
Asymmetrie aldol reaction of ketones with alkenyl trichloroacetates catalyzed by dibutyltin dimethoxide and binap·silver(i) complex: construction of a chiral tertiary carbon center
Yanagisawa, Akira,Terajima, Yuuki,Sugita, Kazuma,Yoshida, Kazuhiro
supporting information; experimental part, p. 1757 - 1762 (2011/02/25)
A novel aldol reaction of alkenyl trichloroacetates with a-keto esters was realized by using dibutyltin dimethoxide as a catalyst, which was regenerated by the addition of methanol. The reaction was found to be remarkably accelerated by the addition of a
Catalytic enantioselective synthesis of α-aminooxy and α-hydroxy ketone using nitrosobenzene
Momiyama, Norie,Yamamoto, Hisashi
, p. 6038 - 6039 (2007/10/03)
The highly enantioselective and O-selective nitroso aldol reaction of tin enolates 2 and nitrosobenzene (1) has been developed with the use of (R)-BINAP-silver complexes as a catalyst. After the various silver salts were surveyed, the AgOTf and the AgClO4 complex were found to be optimal in the O-selective nitroso aldol reaction in both asymmetric induction (up to 97% ee) and regioselection (O/N = >99/1), affording aminooxy ketone 3. The product 3 can be transformed to α-hydroxy ketone 5 without any loss of enantioselectivity. Thus, the method provides an efficient approach to the catalytic enantioselective introduction of oxygen α- to the carbonyl group. Copyright
