trans-2-(N-benzyl)amino-1-cyclohexanol by hydrogenation and subsequent derivatization give access to a broad variety of diversely substituted derivatives. Furthermore, the corresponding cis isomers are readilyavailable. Applications of these optically active aminocyclohexanols in catalyzed asymmetric phenyl transfer reactions to benzaldehydes and transfer hydrogenations of aryl ketones lead to products with
Zinc(II) Perchlorate Hexahydrate Catalyzed Opening of Epoxide Ring by Amines: Applications to Synthesis of (<i>RS</i>)/(<i>R</i>)-Propranolols and (<i>RS</i>)/(<i>R</i>)/(<i>S</i>)-Naftopidils
作者:Shivani、Brahmam Pujala、Asit K. Chakraborti
DOI:10.1021/jo062674j
日期:2007.5.1
perchlorate hexahydrate was found to be the best catalyst compared to other metal perchlorates. The counteranion modulated the catalytic property of the various Zn(II) compounds that followed the order Zn(ClO4)2·6H2O ≫ Zn(BF4)2 ∼ Zn(OTf)2 ≫ ZnI2 > ZnBr2 > ZnCl2 > Zn(OAc)2 > Zn(CO3)2 in parallelism with the acidic strength of the corresponding protic acids (except for TfOH). The applicability of the methodology
Planar Chiral PHANOLs as Double Hydrogen Bonding Donor Organocatalysts: Synthesis and Catalysis
作者:D. Christopher Braddock、Iain D. MacGilp、Benjamin G. Perry
DOI:10.1002/adsc.200404065
日期:2004.8
4,12-Dihydroxy[2.2]paracyclophanediol (PHANOL; 1), and its para-substituted derivatives 2, 5 and 7, were found to catalyse Diels–Alder cycloadditions of α,β-unsaturated aldehydes or ketones with dienes and/or epoxide ringopening reactions with amines. The mode of catalysis by the PHANOLs is via double hydrogen bonding to the two sp2 lone pairs of a carbonyl group or the two lone pairs of the epoxide
发现4,12-二羟基[2.2]对环庚二醇(PHANOL; 1)及其对位取代的衍生物2、5和7可以催化α,β-不饱和醛或酮与二烯和/或环氧化物的狄尔斯-阿尔德环加成反应与胺的开环反应。PHANOLs的催化方式是通过氢键与羰基的两个sp 2孤对或环氧化物的两个孤对进行双氢键合。该PHANOLs的Diels-Alder反应的催化活性的顺序基本上与基于的吸电子基团的能力(一个或多个)的程度在预期的氢键供体强度相关的对位置。相反,由于对双氢键模式的空间干扰,邻位取代的PHANOL 10、11和14没有活性作为催化剂。为支持所提出的双氢键模式,讨论了各种PHANOL的1 H NMR和IR光谱数据。
Zinc Tetrafluoroborate Hydrate as a Mild Catalyst for Epoxide Ring Opening with Amines: Scope and Limitations of Metal Tetrafluoroborates and Applications in the Synthesis of Antihypertensive Drugs (<i>RS</i>)/(<i>R</i>)/(<i>S</i>)-Metoprolols
作者:Brahmam Pujala、Shivani Rana、Asit K. Chakraborti
DOI:10.1021/jo201473f
日期:2011.11.4
reaction at the benzylic carbon of the epoxide ring. A reversal of regioselectivity (91:1–69:31) in favor of the reaction at the terminal carbon of the epoxide ring was observed for reaction with morpholine. The regioselectivity was dependent on the electronic and steric factors of the epoxide and the pKa of the amine and independent of amine nucleophilicity. The role of the metal tetrafluoroborates is
已经研究了金属四氟硼酸盐与胺进行环氧化物开环反应的范围和局限性,并且发现Zn(BF 4)2 · x H 2 O是一种温和而有效的催化剂,在无溶剂条件下于200 ℃提供高收率。 rt具有出色的化学,区域和立体选择性。催化效率依次为Zn(BF 4)2 · x H 2 O≫ Cu(BF 4)2 · x H 2 O> Co(BF 4)2 ·6H 2 O≫ Fe(BF 4)2 ·6H2 O> LiBF 4与环己烯氧化物和Zn(BF 4)2 · x H 2 O≫ Co(BF 4)2 ·6H 2 O≫ Fe(BF 4)2 ·6H 2 O> Cu(BF 4)反应2 · x H 2 O,用于氧化二苯乙烯,但AgBF 4是无效的。对于苯乙烯氧化物与苯胺的反应,四氟硼酸金属具有相当的区域选择性(1:99–7:93),并且在环的苄基碳上具有优先反应。与吗啉反应时,观察到区域选择性的逆转(91:1–69:31),有
Synthesis and structure of an air-stable bis(pentamethylcyclopentadienyl) zirconium pentafluorbezenesulfonate and its application in catalytic epoxide ring-opening reactions
of air-stability, water tolerance, thermally-stability and strong Lewis-acidity. Moreover, the complex showed high catalytic activity and recyclability in catalytic epoxide ring-opening reactions by amines or alcohols. This catalytic system affords a simple and efficient approach for synthesis of β-amino alcohols or β-alkoxy alcohols.
用[(CH 3)5 Cp] 2 ZrCl 2处理C 6 F 5 SO 3 Ag,成功合成了双(五甲基环戊二烯基)五氟苯磺酸锌锆的空气稳定的单核配合物,显示[[((CH 3)通过X射线分析证实了5 Cp} 2 Zr(CH 3 CN)2(H 2 O)] [OSO 2 C 6 F 5 ] 2 · CH 3 CN(1)。综合大楼1还通过其他技术对其进行了表征,发现具有良好的空气稳定性,耐水性,热稳定性和强路易斯酸度。此外,该络合物在胺或醇的催化环氧化物开环反应中显示出高催化活性和可回收性。该催化体系为合成β-氨基醇或β-烷氧基醇提供了一种简单而有效的方法。