Bronsted acid-assisted chiral Lewis acid (BLA) was highly effective as a chiral catalyst for the enantioselective Diels−Alder reaction of both α-substituted and α-unsubstituted α,β-enals with various dienes. Hydroxy groups in opticallyactive binaphthol derivatives and boron reagents with electron-withdrawing substituents were used as Bronsted acids and Lewis acids, respectively. Intramolecular Bronsted
布朗斯台德酸辅助的手性路易斯酸 (BLA) 作为手性催化剂非常有效,可用于 α-取代和 α-未取代的 α,β-烯醛与各种二烯的对映选择性 Diels-Alder 反应。光学活性联萘酚衍生物中的羟基和具有吸电子取代基的硼试剂分别用作布朗斯台德酸和路易斯酸。手性 BLA 催化剂中的分子内布朗斯台德酸在加速 Diels-Alder 反应速率和产生高水平的对映选择性方面发挥了重要作用。特别是,由于手性 BLA 催化剂中羟基芳基在过渡态组装中的分子内氢键相互作用和有吸引力的 π-π 供体-受体相互作用,实现了优异的对映选择性。
Carbocations as Lewis Acid Catalysts in Diels-Alder and Michael Addition Reactions
作者:Juho Bah、Johan Franzén
DOI:10.1002/chem.201304160
日期:2014.1.20
the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) cation was found to be a highly efficient catalyst for the Diels–Alder reaction for a range of substrates. Catalyst loadings as low as 500 ppm, excellent yields, and good endo/exo selectivities were achieved. Furthermore, by changing the electronic properties of the
An examination of VANOL, VAPOL, and VAPOL derivatives as ligands for asymmetric catalytic Diels–Alder reactions
作者:Douglas P Heller、Daniel R Goldberg、Hongqiao Wu、William D Wulff
DOI:10.1139/v06-124
日期:2006.10.1
Several derivatives of the vaultedbiarylligand VAPOL were prepared and evaluated as chiralligands for aluminum Lewis acids in the catalyticasymmetricDiels–Alderreactions of methyl acrylate an...
New Lewis acid catalysts for the Diels-Alder reaction
作者:T. Ross Kelly、Sanat K. Maity、Premji Meghani、Nizal S. Chandrakumar
DOI:10.1016/s0040-4039(00)99464-4
日期:1989.1
Catechol boron bromide (1) and ferrocenium hexafluorophosphate (2) function as Lewisacidcatalysts for the Diels-Alderreaction.
儿茶酚溴化硼(1)和六氟磷酸铯(2)充当Diels-Alder反应的路易斯酸催化剂。
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。