Showing papers by "Hiroaki Sasai published in 2017"
TL;DR: Mixing of acryloylchloride, dienone 2, N,N-diisopropylethylamine with chiral organocatalyst 5a led to a one-pot amidation/Rauhut-Currier sequence, affording α-methylidene-γ-lactams 4.
38 citations
TL;DR: A mechanism-driven enantiodivergent approach to chiral 1,1'-bi-2-naphthols via catalytic asymmetric oxidative coupling of 2- naphthol derivatives is described for the first time.
31 citations
TL;DR: In this paper, the authors demonstrate that the crystalline sponge method provides an effective way to crystallographically determine the absolute configuration of organic compounds bearing chiral quaternary carbons (including tetra-substituted ones) that are synthesized by enantioselective catalytic reactions.
Abstract: Determination of the absolute configuration of chiral tetra-substituted carbon centers is one of the most taxing steps in the enantioselective construction of this structural motif in asymmetric synthesis. Here, we demonstrate that the crystalline sponge method provides an effective way to crystallographically determine the absolute configuration of organic compounds bearing chiral quaternary carbons (including tetra-substituted ones) that are synthesized by recently developed enantioselective catalytic reactions.
30 citations
TL;DR: Short syntheses of 4-deoxycarbazomycin B and sorazolon E were established through the condensation of cyclohexanone and commercially available 4-methoxy-2,3-dimethylaniline, followed by PdII -catalyzed dehydrogenative aromatization/intramolecular C-C bond coupling and deprotection.
Abstract: Short-step syntheses of 4-deoxycarbazomycin B and sorazolon E were established through the condensation of cyclohexanone and commercially available 4-methoxy-2,3-dimethylaniline, followed by Pd(II)-catalyzed dehydrogenative aromatization/intramolecular C-C bond coupling and deprotection. A chiral dinuclear vanadium complex (Ra,S,S)-6 mediated the first enantioselective oxidative coupling of sorazolon E, affording (+)-sorazolon E2 in good enantioselectivity.
20 citations
TL;DR: The highly enantioselective cyclization of 3-alkenylindole via C-H activation has been established using Pd(OCOCF3)2 in conjunction with the chiral spiro bis(isoxazoline) ligand (SPRIX) to produce tricyclic indole products with chiral quaternary carbon center.
18 citations
TL;DR: The reaction of phenols and N-tosylimines bearing a Michael acceptor moiety afforded densely functionalized 1,3-disubstituted isoindolines bearing two stereogenic centers as single diastereomers in high yields and excellent enantioselectivities.
18 citations
TL;DR: An enantioselective intermolecular Rauhut-Currier reaction of nitroalkenes with ethyl allenoate has been established with quinidine-derived β-isocupreidine and afforded α-functionalized allenoates 3 in up to 94% yield with 59% enantiomeric excess.
Abstract: An enantioselective intermolecular Rauhut-Currier (RC) reaction of nitroalkenes with ethyl allenoate has been established with quinidine-derived β-isocupreidine. The present RC reaction afforded α-functionalized allenoates 3 in up to 94% yield with 59% enantiomeric excess (ee).
6 citations