Design of <i>N</i>-Spiro <i>C</i><sub>2</sub>-Symmetric Chiral Quaternary Ammonium Bromides as Novel Chiral Phase-Transfer Catalysts: Synthesis and Application to Practical Asymmetric Synthesis of α-Amino Acids
作者:Takashi Ooi、Minoru Kameda、Keiji Maruoka
DOI:10.1021/ja021244h
日期:2003.4.1
C(2)-symmetric chiralquaternaryammonium bromides 10 and 11 have been designed as a new, purely synthetic chiral phase-transfer catalyst, and readily prepared from commercially available optically pure 1,1'-bi-2-naphthol as a basic chiral unit. The details of the synthetic procedures of each requisite chiral binaphthyl subunit have been disclosed, and the structures of the assembled N-spiro chiral quaternary
Chiral Aminophosphines as Catalysts for Enantioselective Double-Michael Indoline Syntheses
作者:San N. Khong、Ohyun Kwon
DOI:10.3390/molecules17055626
日期:——
The bisphosphine-catalyzed double-Michael addition of dinucleophiles to electron-deficient acetylenes is an efficient process for the synthesis of many nitrogen-containing heterocycles. Because the resulting heterocycles contain at least one stereogenic center, this double-Michael reaction would be even more useful if an asymmetric variant of the reaction were to be developed. Aminophosphines can also facilitate the double-Michael reaction and chiral amines are more readily available in Nature and synthetically; therefore, in this study we prepared several new chiral aminophosphines. When employed in the asymmetric double-Michael reaction between ortho-tosylamidophenyl malonate and 3-butyn-2-one, the chiral aminophosphines produced indolines in excellent yields with moderate asymmetric induction.
Oxygen‐Linked Cyclopentadienyl Rhodium(III) Complexes‐Catalyzed Asymmetric C−H Arylation of Benzo[
<i>h</i>
]quinolines with 1‐Diazonaphthoquinones
作者:Chongqing Pan、Si‐Yong Yin、Shao‐Bo Wang、Qing Gu、Shu‐Li You
DOI:10.1002/anie.202103638
日期:2021.7.5
functionalization reactions have witnessed a significant progress in organic synthesis. In sharp contrast, the reported chiral Cp ligands are limited to C-linked Cp and are often synthetically challenging. To address these issues, we have developed a novel class of tunable chiral cyclopentadienyl ligands bearing oxygen linkers, which were efficient catalysts for C−H arylation of benzo[h]quinolines with
Enantioselective Iron/Bisquinolyldiamine Ligand-Catalyzed Oxidative Coupling Reaction of 2-Naphthols
作者:Lin-Yang Wu、Muhammad Usman、Wen-Bo Liu
DOI:10.3390/molecules25040852
日期:——
An iron-catalyzed asymmetric oxidative homo-coupling of 2-naphthols for the synthesis of 1,1′-Bi-2-naphthol (BINOL) derivatives is reported. The couplingreaction provides enantioenriched BINOLs in good yields (up to 99%) and moderate enantioselectivities (up to 81:19 er) using an iron-complex generated in situ from Fe(ClO4)2 and a bisquinolyldiamine ligand [(1R,2R)-N1,N2-di(quinolin-8-yl)cyclohexane-1