La(OTf) 3催化的[3+2]环加成反应通过醌和1,2-二叔丁基-3-(氰胺基)二氮丙啶合成苯并[ d ]恶唑/苯并呋喃(1,3-二叔丁基-2-氰基胍)/乙烯基叠氮化物已被探索。方便地得到了一系列5-羟基苯并呋喃-4-甲酸衍生物和5-羟基苯并[ d ]恶唑-4-甲酸衍生物,收率高,立体选择性好,可用于进一步转化为有价值的化合物。
Alkyl and alkoxycarbonyl radicals were generated by oxidative decarboxylation of oxalic acid monoesters by persulfate; they were then utilized for the selective substitution of quinones.
Peptide‐Catalyzed Fragment Couplings that Form Axially Chiral Non‐
<i>
C
<sub>2</sub>
</i>
‐Symmetric Biaryls
作者:Gavin Coombs、Marcus H. Sak、Scott J. Miller
DOI:10.1002/anie.201913563
日期:2020.2.10
We have demonstrated that small, modular, tetrameric peptides featuring the Lewis-basic residue β-dimethylaminoalanine (Dmaa) are capable of atroposelectively coupling naphthols and ester-bearing quinones to yield non-C2 -symmetric BINOL-type scaffolds with good yields and enantioselectivity. The study culminates in the asymmetric synthesis of backbone-substituted scaffolds similar to 3,3'-disubstituted
Organocatalytic Enantioselective Synthesis of Atropisomeric Aryl‐
<i>p</i>
‐Quinones: Platform Molecules for Diversity‐Oriented Synthesis of Biaryldiols
作者:Ye‐Hui Chen、Heng‐Hui Li、Xiao Zhang、Shao‐Hua Xiang、Shaoyu Li、Bin Tan
DOI:10.1002/anie.202004671
日期:2020.7.6
Presented here is a class of novel axiallychiral aryl‐p ‐quinones as platform molecules for the preparation of non‐C2symmetric biaryldiols. Two sets of aryl‐p ‐quinone frameworks were synthesized with remarkable enantiocontrol by means of chiral phosphoric acid catalyzed enantioselective arylation of p ‐quinones by central‐to‐axialchirality conversion. These aryl‐p ‐quinones were then used to access
axially chiral biaryldiols via asymmetric Friedel–Crafts aromatization between p-quinones and 2-naphthols was developed. A chiral cobalt(II) complex of N,N′-dioxide enabled the process to generate axially chiral biaryldiols in up to 98% yield and 95% ee. A large range of substituents at different positions of p-quinones and 2-naphthols was tolerable. The configuration of the product and the chiral N,N′-dioxide-Co(ClO4)2
Nuclear Amination Catalyzed by Fungal Laccases: Reaction Products of <i>p</i>-Hydroquinones and Primary Aromatic Amines
作者:Timo H. J. Niedermeyer、Annett Mikolasch、Michael Lalk
DOI:10.1021/jo048454s
日期:2005.3.1
amination of p-hydroquinones with primaryaromaticamines was catalyzed by fungal laccases (EC 1.10.3.2) from Trametes spec. and Myceliophthora thermophila. This is the first report of laccase-catalyzed synthesis of aminoquinones. Incubation of two compounds with laccase in the presence of oxygen resulted in the formation of the corresponding monoaminated or diaminated quinones. No hydroquinonoids were formed