A Simple, Modular Synthesis of Substituted Pyridines
作者:Songbai Liu、Lanny S. Liebeskind
DOI:10.1021/ja8013743
日期:2008.6.1
A simple, modular method to prepare highly substitutedpyridines is disclosed. The method employs a cascade reaction comprising (1) a novel N-iminative, Cu-catalyzed cross-coupling of alkenylboronic acids at the N-O bond of alpha,beta-unsaturated ketoxime O-pentafluorobenzoates, (2) electrocyclization of the resulting 3-azatriene, and (3) air oxidation affording highly substitutedpyridines in moderate
Borane-Catalyzed, Chemoselective Reduction and Hydrofunctionalization of Enones Enabled by B–O Transborylation
作者:Kieran Nicholson、Thomas Langer、Stephen P. Thomas
DOI:10.1021/acs.orglett.1c00446
日期:2021.4.2
The use of stoichiometric organoborane reductants in organic synthesis is well established. Here these reagents have been rendered catalytic through an isodesmic B–O/B–H transborylation applied in the borane-catalyzed, chemoselectivealkenereduction and formal hydrofunctionalization of enones. The reaction was found to proceed by a 1,4-hydroboration of the enone and B–O/B–H transborylation with HBpin
Discovery of trisubstituted pyrazolines as a novel scaffold for the development of selective phosphodiesterase 5 inhibitors
作者:Mohammad Abdel-Halim、Heather Tinsley、Adam B. Keeton、Mohammed Weam、Noha H. Atta、Mennatallah A. Hammam、Amr Hefnawy、Rolf W. Hartmann、Matthias Engel、Gary A. Piazza、Ashraf H. Abadi
DOI:10.1016/j.bioorg.2020.104322
日期:2020.11
modifications led to new PDE5 inhibitors with approximately 20-fold improved potency to inhibit PDE5 and no COX-2 inhibitory activity compared with celecoxib. PDE isozyme profiling of compound 11 revealed a favorable selectivityprofile. These results suggest that trisubstituted pyrazolines provide a promising scaffold for further chemical optimization to identify novel PDE5 inhibitors with potential for less
Controlling the Molecular Topology of Vinylogous Iminium Ions by Logical Substrate Design: Highly Regio- and Stereoselective Aminocatalytic 1,6-Addition to Linear 2,4-Dienals
about topologycontrol: The title reaction yields valuable tetrahydrofuran spirooxindoles (see scheme; TMS=trimethylsilyl), and exemplifies a rare asymmetric 1,6‐addition to linear 2,4‐dienals proceeding with high δ‐site‐ and stereoselectivity. A steering group at the β‐dienal position ensured molecular preorganization of the catalytically active vinylogousiminiumion intermediate for highly predictable
NBS-mediated cyclization of trans-cinnamic alcohols
作者:Meng-Yang Chang、Chung-Yu Tsai、Ming-Hao Wu
DOI:10.1016/j.tet.2013.05.110
日期:2013.8
An efficient and straightforward three-step synthetic route toward 2,4-disubstituted-3-bromooxetanes 5 with the trans–trans contiguous stereogenic centers is developed from functionalized chalcones 3 via NaBH4-mediated reduction of chalcones 3, followed by NBS-mediated electrophilic cyclization of the resulting trans-cinnamic alcohols 4 in good yield. Skeleton 3 is prepared by Claisen–Schmidt condensation