- Chiral urea-based ligand and preparation method thereof
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The invention discloses a chiral urea-based ligand and a preparation method thereof. The preparation method comprises the following steps: step 1, dissolving a chiral amine and isocyanate or isothiocyanate into an organic solvent according to a molar ratio of 1:(1-1.2), and performing full mixing; and step 2, performing a reaction at a temperature of -5 DEG C to 35 DEG C for 1-18 h, and performingcolumn chromatography purification to obtain the desired chiral urea-based ligand. The chiral urea-based ligand obtained by the method has a non-simple linear chain in the molecular structure and a soft skeleton in the molecular structure; the chiral urea-based ligand can utilizes multiple hydrogen-bond interaction of the urea structure to activate an electrophilic reagent or a nucleophilic reagent to improve the catalytic performance; and the chiral urea-based ligand has high enantioselectivity and high reactivity in an asymmetric reaction, the preparation method is simple, the steps are few, and the raw materials are cheap and easy to obtain.
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- Asymmetric addition of terminal alkynes to n-(Diphenylphosphinoyl)imines promoted by stoichiometric amounts of a proline-derlved ss-amino alcohol
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A new synthetic methodology for the preparation of optically active propargylamines is described. The alkynylation of aromatic, heteroaromatic, aliphatic and α,β-unsaturated N-(di-phenylphosphinoyl)imines was investigated by using dieth-ylzinc and a proline-derived β-amino alcohol, N-(Diphenylphosphinoyl)-protected propargylic amines can be synthesized in high yields and with good to excellent: enantio-selectivities.
- Yan, Wenjin,Mao, Bin,Zhn, Shaoqun,Jiang, Xianxing,Liu, Zhongli,Wang, Rui
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supporting information; experimental part
p. 3790 - 3794
(2009/12/07)
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- LARGE SCALE PREPARATION OF VERSATILE CHIRAL AUXILIARIES DERIVED FROM (S)-PROLINE
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The synthesis of a variety of enantiomerically pure chiral auxiliaries based on (S)-proline and bearing sterically demanding side chains at the pyrrolidine moiety, such as the secondary amines (S)-3,5 and 7 and the hydrazines (S)-6, is described on a molar scale.As key step, the Grignard or RLi addition to the N-benzylated proline ester (S)-1 is used.
- Enders, Dieter,Kipphardt, Helmut,Gerdes, Peter,Brena-Valle, Leonardo J.,Bhushan, Vidya
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p. 691 - 704
(2007/10/02)
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