23439-90-9Relevant articles and documents
Versatile and Enantioselective Preparation of Planar-Chiral Metallocene-Fused 4-Dialkylaminopyridines and Their Application in Asymmetric Organocatalysis
Yoshida, Kazuhiro,Liu, Qiang,Yasue, Risa,Wada, Shiro,Kimura, Ryosuke,Konishi, Takuma,Ogasawara, Masamichi
, p. 292 - 301 (2020)
A series of ferrocene-fused planar-chiral N-tosyl-4-pyridones (S)-2b-d were prepared in enantiomerically pure forms. Starting with the chiral ferrocenyl acetals, 1-[(2S,4S)-4-methoxymethyl-1,3-dioxan-2-yl]-1′,2′,3′,4′,5′-R5-ferrocenes ((-)-3b,
PQXdpap: Helical Poly(quinoxaline-2,3-diyl)s Bearing 4-(Dipropylamino)pyridin-3-yl Pendants as Chirality-Switchable Nucleophilic Catalysts for the Kinetic Resolution of Secondary Alcohols
Murakami, Ryo,Suginome, Michinori,Yamamoto, Takeshi
supporting information, p. 8711 - 8716 (2021/11/24)
Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-(dipropylamino)pyridin-3-yl pendants at the 5-position of the quinoxaline ring (PQXdpap) exhibited high catalytic activities and moderate to high selectivities (up to s = 87) in the acylative kinetic resolution of secondary alcohols. The solvent-dependent helical chirality switching of PQXdpap between pure toluene and a 1:1 mixture of toluene and 1,1,2-trichloroethane enabled the preparation of either compound of a pair of enantiomerically pure alcohols (>99% ee) from a single catalyst.
Enantioselective synthesis of planar-chiral ferrocene-fused 4-pyridones and their application in construction of pyridine-based organocatalyst library
Ogasawara, Masamichi,Wada, Shiro,Isshiki, Erika,Kamimura, Takumi,Yanagisawa, Akira,Takahashi, Tamotsu,Yoshida, Kazuhiro
supporting information, p. 2286 - 2289 (2015/05/13)
A couple of planar-chiral ferrocene-fused 4-pyridone derivatives 2a and 2b were synthesized in enantiomerically pure form by scalable asymmetric transformations. Pyridones 2 are versatile precursors to various ferrocene-fused pyridine derivatives, which a
Kinetic resolution of secondary alcohols by chiral dmap derivatives prepared by the Ugi multicomponent reaction
Mandai, Hiroki,Irie, Shunsuke,Akehi, Masaru,Yuri, Kazunobu,Yoden, Masaaki,Mitsudo, Koichi,Suga, Seiji
, p. 329 - 340 (2013/03/28)
The kinetic resolution of secondary alcohols was examined by new chiral DMAP derivatives, which can readily be prepared by the Ugi multicomponent reaction in a one-pot operation. The initial screening of DMAP derivatives indicated that the catalyst bearing L-valine with an S configuration at the a-position of amide showed the best stereoselectivity factor. After the reaction conditions were optimized with (S,S)-4a in the kinetic resolution of secondary alcohols, various acyclic and cyclic secondary alcohols could be resolved with an s -factor of up to 12.
A highly enantioselective phosphabicyclooctane catalyst for the kinetic resolution of benzylic alcohols
Vedejs, Edwin,Daugulis, Olafs
, p. 4166 - 4173 (2007/10/03)
A new class of chiral phosphines belonging to the P-aryl-2-phosphabicyclo[3.3.0]octane family (PBO) has been prepared by enantioselective synthesis starting from lactate esters and 2,2-dimethylcy-clopentanone enolate 5. A selective enolate alkylation method has been developed for preparation of 9 and 10 using a chelating ester substituent in the triflate alkylating agent 11. Subsequent conversion to the PBO catalysts 2 and 39 relies on a diastereoselective cyclization from the cyclic sulfate 17 and LiPHAr to afford the more hindered endo-aryl phosphines. These phosphines function as efficient catalysts for the kinetic resolutions of aryl alkyl carbinols by benzoylation (16, 21, 22) or iso-butyroylation in the case of the less hindered aryl alkyl carbinol substrates. With o-substituted aryl alkyl carbinols, the enantioselectivities exceed 100, and s = 380 ± 10 has been demonstrated in the case of methyl mesityl carbinol. The PBO- catalyzed acylations probably involve a P-acylphosphonium carboxylate intermediate and a tightly ion paired transition state.
A new nucleophilic catalyst for kinetic resolution of racemic sec-alcohols
Jeong, Kyu-Sung,Kim, Soong-Hyun,Park, Hyun-Jin,Chang, Kyoung-Jin,Kwan, Soo Kim
, p. 1114 - 1115 (2007/10/03)
A new tertiary amine-based nucleophilic catalyst, derived from a simple combination of commercially available compounds, affords good to excellent kinetic resolution of racemic sec-alcohols.
Selection of enantioselective acyl transfer catalysts from a pooled peptide library through a fluorescence-based activity assay: An approach to kinetic resolution of secondary alcohols of broad structural scope
Copeland,Miller
, p. 6496 - 6502 (2007/10/03)
An assay employing a fluorescently labeled split and pool peptide library has been applied to the discovery of a new class of octapeptide catalysts for the kinetic resolution of secondary alcohols. A highly diverse library of peptide-based catalysts was synthesized on solid-phase synthesis beads such that each individual bead was co-functionalized with (i) a uniform loading of a pH-sensitive fluorophore and (ii) a unique peptidebased catalyst. The library was then screened for activity in acylation reactions employing (±)-sec-phenylethanol as the substrate and acetic anhydride as the acylation agent. From the most active catalysts, a lead peptide (4) was identified that provides a selectivity-factor (krel) of 8.2 upon resynthesis and evaluation under homogeneous conditions. A "directed" second-generation split and pool peptide library was synthesized such that the new peptide sequences in the library were biased toward the lead structure. Random samples of the second generation library were screened in single bead assays that revealed several new peptide-based catalysts that afford improved selectivities in kinetic resolutions. Peptide catalyst 13 proves effective for the kinetic resolution of sec-phenylethanol (krel = 20), as well as eight other secondary alcohols of a broad substrate scope (krel = 4 to > 50).