88481-75-8Relevant articles and documents
Enantioselective Desymmetrization of 2-Aryl-1,3-propanediols by Direct O-Alkylation with a Rationally Designed Chiral Hemiboronic Acid Catalyst That Mitigates Substrate Conformational Poisoning
Estrada, Carl D.,Ang, Hwee Ting,Vetter, Kim-Marie,Ponich, Ashley A.,Hall, Dennis G.
supporting information, (2021/04/07)
Enantioselective desymmetrization by direct monofunctionalization of prochiral diols is a powerful strategy to prepare valuable synthetic intermediates in high optical purity. Boron acids can activate diols toward nucleophilic additions; however, the design of stable chiral catalysts remains a challenge and highlights the need to identify new chemotypes for this purpose. Herein, the discovery and optimization of a bench-stable chiral 9-hydroxy-9,10-boroxarophenanthrene catalyst is described and applied in the highly enantioselective desymmetrization of 2-aryl-1,3-diols using benzylic electrophiles under operationally simple, ambient conditions. Nucleophilic activation and discrimination of the enantiotopic hydroxy groups on the diol substrate occurs via a defined chairlike six-membered anionic complex with the hemiboronic heterocycle. The optimal binaphthyl-based catalyst 1g features a large aryloxytrityl group to effectively shield one of the two prochiral hydroxy groups on the diol complex, whereas a strategically placed "methyl blocker"on the boroxarophenanthrene unit mitigates the deleterious effect of a competing conformation of the complexed diol that compromised the overall efficiency of the desymmetrization process. This methodology affords monoalkylated products in enantiomeric ratios equal or over 95:5 for a wide range of 1,3-propanediols with various 2-aryl/heteroaryl groups.
Fluorinated Pseudopeptide Analogues of the Neuropeptide 26RFa: Synthesis, Biological, and Structural Studies
Pierry, Camille,Couve-Bonnaire, Samuel,Guilhaudis, Laure,Neveu, Cindy,Marotte, Amelie,Lefranc, Benjamin,Cahard, Dominique,Segalas-Milazzo, Isabelle,Leprince, Jerome,Pannecoucke, Xavier
, p. 1620 - 1633 (2013/09/23)
A series of four fluorinated dipeptide analogues each containing a fluoro-olefin moiety as peptide bond surrogate has been designed and synthesized. These motifs have been successfully introduced into the bioactive C-terminal heptapeptide of the neuropeptide 26RFa by conventional SPPS. We then evaluated the ability of the generated pseudopeptides to increase [Ca2+]i in GPR103-transfected cells. For these fluorinated analogues, greater stability in human serum was observed. Their conformations were also investigated, leading to the valuable identification of differences depending on the position of the fluoro-olefin moiety in the sequence.
Enantioselective aldol chemistry via alkyl enol ethers. Scope of the Lewis acid catalyzed condensation of optically active trimethylsilyl and methyl 2-[(E)-1-alkenyloxy]ethanoates with acetals
Faunce, James A.,Grisso, Bryan A.,Mackenzie, Peter B.
, p. 3418 - 3426 (2007/10/02)
Optically active, mono- and disubstituted trimethylsilyl 2-[(E)-1-alkenyloxy]ethanoates of the type RR1CH = CHOCHR2CO2SiMe3 (R = Me, PhCH2, n-Bu, MeO2CCMe2CH2, PhSCHs
