Enantioselective Synthesis of Vicinal Halohydrins via Dynamic Kinetic Resolution
作者:Abel Ros、Antonio Magriz、Hansjörg Dietrich、Rosario Fernández、Eleuterio Alvarez、José M. Lassaletta
DOI:10.1021/ol052821k
日期:2006.1.1
[reaction: see text] Expanding the scope of enantioselective catalysis via DKR, transfer hydrogenation of a variety of cyclic alpha-halo ketones was accomplished using the Noyori/Ikariya (R,R)- or (S,S)-I catalysts and either HCO(2)H/Et(3)N or HCO(2)Na/n-Bu(4)NBr in H(2)O/CH(2)Cl(2) as the hydrogen sources. Good yields of vicinal bromo-, chloro-, and fluorohydrins with excellent de and ee levels were
Convincing Catalytic Performance of Oxo-Tethered Ruthenium Complexes for Asymmetric Transfer Hydrogenation of Cyclic α-Halogenated Ketones through Dynamic Kinetic Resolution
A highly efficient dynamic kinetic resolution of cyclic halohydrins was achieved by the asymmetric transfer hydrogenation of racemic α-haloketones. Bifunctional oxo-tethered Ru(II) catalysts could promote the reduction without deterioration of halogens. By structural tuning of the catalyst, chiral alcohols having halogen, ester, carboxamide, and sulfone functions were obtained variably with excellent
The photoinduced reductive dehalogenation promiscuity of cyclohexanonemonooxygenase (CHMO) with a novel mechanism of ET/PT distinct from the photoinducedpromiscuity of natural reductases is reported. Various highly enantioenriched α-fluoroketones were synthesized by photoinduced reductive dehalogenation of α,α-halofluoroketones in a process catalyzed by the rationally designed CHMO mutants.
Enantioselective Bromination of Silyl Enol Ethers with Chiral Pentacarboxycyclopentadienyl Bromide
作者:Pingfan Li、Guo Liu
DOI:10.1055/a-2088-9219
日期:2023.12
Chiral pentacarboxycyclopentadienyl bromide reagents were synthesized to accomplish enantioselective bromination of silylenolethers to give corresponding α-bromoketone products in good yields and up to 77% ee. A catalytic version of this reaction was also demonstrated through the combination of Lewis acid activators and diethyl 2,2-dibromomalonate as stoichiometric achiral bromine source.
合成了手性五羧基环戊二烯基溴化试剂,以实现甲硅烷基烯醇醚的对映选择性溴化,以良好的产率和高达 77% ee 得到相应的 α-溴酮产物。该反应的催化形式也通过路易斯酸活化剂和 2,2-二溴丙二酸二乙酯的组合作为化学计量的非手性溴源得到证明。