发现很少使用的硼路易斯酸三[3,5-双(三氟甲基)苯基]硼烷(BAr F 3)是无金属亚胺加氢硼化的极佳催化剂。在1.0mol%的BAr F 3的存在下,几种酮亚胺和醛亚胺在室温下与频哪醇硼烷(HBpin)进行硼氢化反应,而无需外部路易斯碱的帮助。BAr F 3比其他路易斯酸性硼烷,包括经常使用的三(五氟苯基)硼烷(B(C 6 F 5)3),具有更高的反应性。B(C 6 F 5)3中六个氟原子邻位赋予硼中心的空间位阻占这个。机械控制实验表明常规的路易斯酸催化涉及亚胺活化和从HBpin转移氢化物。
<scp>l</scp>-Piperazine-2-carboxylic Acid Derived <i>N</i>-Formamide as a Highly Enantioselective Lewis Basic Catalyst for Hydrosilylation of <i>N</i>-Aryl Imines with an Unprecedented Substrate Profile
作者:Zhouyu Wang、Mounuo Cheng、Pengcheng Wu、Siyu Wei、Jian Sun
DOI:10.1021/ol060984i
日期:2006.7.1
l-Piperazine-2-carboxylic acid derived N-formamides have been developed as highlyenantioselectiveLewis basic catalysts for the hydrosilylation of N-aryl imines with trichlorosilane. The arene sulfonyl group on N4 was found to be critical for the high enantioselectivity of the catalyst. High isolated yields (up to 99%) and enantioselectivities (up to 97%) were obtained for a broad range of substrates, including
Evolution of chiral Lewis basic N-formamide as highly effective organocatalyst for asymmetric reduction of both ketones and ketimines with an unprecedented substrate scope
作者:Li Zhou、Zhouyu Wang、Siyu Wei、Jian Sun
DOI:10.1039/b703307a
日期:——
L-Pipecolinic acid derived Lewis basic N-formamide has been developed as a first highly effective catalyst for the asymmetric reduction of aromatic and aliphatic ketones as well as aromatic and aliphatic ketimines in good to high enantioselectivity.
<i>S</i>-Chiral Sulfinamides as Highly Enantioselective Organocatalysts
作者:Dong Pei、Zhouyu Wang、Siyu Wei、Yu Zhang、Jian Sun
DOI:10.1021/ol062633+
日期:2006.12.1
accessible chiral sulfinamide 2 has been developed as the first highly efficient and enantioselectiveorganocatalyst relying solely on a chiral sulfur center for stereochemical induction. In the presence of 20 mol % of 2, a broad range of N-aryl ketimines 1 were reduced by trichlorosilane to produce amines 3 in high yield and enantioselectivity. [reaction: see text]
Formamides derived from N-methyl amino acids serve as new chiral organocatalysts in the enantioselective reduction of aromatic ketimines with trichlorosilane
作者:Andrei V. Malkov、Sigitas Stončius、Kenneth N. MacDougall、Andrea Mariani、Grant D. McGeoch、Pavel Kočovský
DOI:10.1016/j.tet.2005.08.117
日期:2006.1
Asymmetric reduction of N-aryl ketimines 1a–k, 43, and 45 with trichlorosilane can be catalyzed by new N-methyl l-amino acid-derived Lewis-basic organocatalysts, such as the valine-derived bisamide 3d (10 mol%), in toluene at room temperature with high enantioselectivity (≤92% ee). The structure–reactivity investigation shows that the product configuration is controlled by the nature of the side chain
N-芳基酮亚胺1a - k,43和45用三氯硅烷的不对称还原可以由新的N-甲基l-氨基酸衍生的Lewis碱性有机催化剂催化,例如缬氨酸衍生的双酰胺3d(10 mol%),在室温下在甲苯中具有高对映选择性(≤92%ee)。结构反应研究表明,产物构型受催化剂支架侧链性质的控制(例如,在3d和6e中,i -Pr vs Me)),因此相同绝对构型的催化剂可能会诱导产物相反的对映异构体的形成。催化剂与传入的亚胺之间的芳烃-芳烃相互作用似乎是不对称诱导的前提。这种无金属的有机催化方案与传统的金属催化方法相比具有竞争优势。
A Highly Enantioselective Lewis Basic Organocatalyst for Reduction of <i>N</i>-Aryl Imines with Unprecedented Substrate Spectrum
作者:Zhouyu Wang、Xiaoxia Ye、Siyu Wei、Pengcheng Wu、Anjiang Zhang、Jian Sun
DOI:10.1021/ol060112g
日期:2006.3.2
L-Pipecolinic acid derived formamides have been developed as highly efficient and enantioselective Lewis basic organocatalysts for the reduction of N-aryl imines with trichlorosilane. Catalyst 4b afforded high isolated yields (up to 98%) and enantioselectivities (up to 96%) under mild conditions with an unprecedented substrate spectrum.