Divergent Synthesis of Chiral Covalent Organic Frameworks
作者:Li‐Ke Wang、Jing‐Jing Zhou、Yu‐Bao Lan、San‐Yuan Ding、Wei Yu、Wei Wang
DOI:10.1002/anie.201903534
日期:2019.7.8
introduce functionality, in a divergent manner, into covalentorganicframeworks (COFs). This modular protocol includes two stages of covalentassembly, through which functional COFs can be constructed by a three‐step transformation of a key platform molecule, such as 4,7‐dibromo‐2‐chloro‐1H‐benzo[d]imidazole (DBCBI). Constructed herein are four types of chiral COFs (CCOFs) from DBCBI by nucleophilic substitution
Chiral Cobalt(III) Tris(1,2-diamine) Catalysts That Incorporate Nitrogenous Base Containing Anions for the Bifunctional Activation of Nucleophiles and Electrophiles in Enantioselective Addition Reactions
作者:Connor Q. Kabes、Reagan F. Lucas、Jack H. Gunn、John A. Gladysz
DOI:10.1021/acscatal.1c01883
日期:2021.7.2
The lipophilic diastereomeric cobalt complexes Λ or Δ-[Co((S,S)-dpen)3]3+ 2Cl–BArf– (Λ or Δ-(S,S)-23+ 2Cl–BArf–; dpen/BArf– = 1,2-diphenylethylenediamine/B(3,5-C6H3(CF3)2)4–) catalyze a number of enantioselective C–H bond addition reactions in the presence of aliphatic tertiaryamines, but pyridine and N,N-dimethylaniline are much less effective. However, when these bases are incorporated into counter
亲脂性非对映钴配合物 Λ 或 Δ-[Co(( S , S )-dpen) 3 ] 3+ 2Cl – BAr f – (Λ 或 Δ-( S , S )- 2 3+ 2Cl – BAr f – ; dpen /BAr f – = 1,2-二苯基乙二胺/B(3,5-C 6 H 3 (CF 3 ) 2 ) 4 – ) 在脂肪族叔胺存在下催化许多对映选择性的 C–H 键加成反应,但吡啶和N ,N-二甲基苯胺的效果要差得多。然而,当这些碱以 Λ 或 Δ-( S , S )- 2 3+ 4 – Cl – BAr f – 的形式结合到抗衡阴离子 ( 4 – ) 中时,可以实现高度对映选择性的双功能催化剂。烟酸盐、异烟酸盐、相关磺酸盐和N , N-二甲氨基苯甲酸酯是有效的。6-氯烟酸盐提供较慢的速率和较低的ee值,而6-氨基烟酸盐提供较快的速率和较高的ee值。6-甲基、2-甲氧基和未取代的类似物提供中间结果
Readily Available Chiral Benzimidazoles-Derived Guanidines as Organocatalysts in the Asymmetric α-Amination of 1,3-Dicarbonyl Compounds
α-amination of 1,3-dicarbonylcompounds using di-t-butylazodicarboxylate as aminating agent is herein disclosed. The catalysts are readily synthesized through the reaction of 2-chlorobezimidazole and a chiral amine in moderate-to-good yields. Among all of them, those derived from (R)-1-phenylethan-1-amine (1) and (S)-1-(2-naphthyl)ethan-1-amine (3) turned out to be the most efficient for such asymmetric transformation
Tris(1,2-diphenylethylenediamine)cobalt(III) Complexes: Chiral Hydrogen Bond Donor Catalysts for Enantioselective α-Aminations of 1,3-Dicarbonyl Compounds
作者:Anil Kumar、Subrata K. Ghosh、John A. Gladysz
DOI:10.1021/acs.orglett.6b00023
日期:2016.2.19
The enantiopure salt Δ-[Co((S,S)-dpen)3]3+2Cl–B(C6F5)4– is an effective hydrogen bond donor catalyst for additions of 1,3-dicarbonyl compounds to di-tert-butyl azodicarboxylate in the presence of N-methylmorpholine (1.0:1.0:0.10) in CH3CN at 0 °C, as illustrated with educts derived from five- or six-membered ring ketones (99–88% yields, >99–91% ee) and cycloheptanone (94%, 72% ee) as well as 2-cyanocyclopentanone
(+)-Cinchonine-Decorated Dendrimers as Recoverable Organocatalysts
作者:Jordi Rull、Martí Casals、Rosa M. Sebastián、Adelina Vallribera、Jean-Pierre Majoral、Anne-Marie Caminade
DOI:10.1002/cctc.201500580
日期:2015.9.1
First‐ and fourth‐generation phosphorus dendrimers decorated on their surface with (+)‐cinchonine moieties for the use as organocatalysts have been prepared. The first‐generation dendrite showed the highest activity and enantioselectivity in the α‐amination of several β‐dicarbonyl compounds. A positive dendritic effect was observed. Its recovery and reuse over 10 cycles was demonstrated without loss