Catalytic Enantioselective Carbon Insertion into the β-Vinyl C–H Bond of Cyclic Enones
摘要:
Chiral oxazaborolidinium ion-catalyzed C-sp(2)-H functionalization of enones using diazoacetate has been developed. Various beta-substituted cyclic enones were synthesized in high yield (up to 99%) with high to excellent enantioselectivity (up to 99% ee). The synthetic utility of this reaction was demonstrated by the formal synthesis of (+)-epijuvabione.
chemical reagents has played an essential role in the treatment of human diseases. However, the reagents currently used are limited to the covalent modification of cysteine and lysine residues. It is thus desirable to develop novel methods that can covalently modify other residues. Despite the fact that the carboxyl residues are crucial for maintaining the protein function, few selective labeling reactions
Bakers’ yeast reduces esters of 2-alkyl-3-oxobutanoic acid (CH3COCHRCO2R′; R=methyl, ethyl, propyl, propargyl, and allyl) into the corresponding (S)-hydroxy esters with exclusive stereoselectivity, while the configuration at the 2-position of the hydroxy esters is either S (anti) or R (syn) depending on the structure of the alkoxyl group in the carboalkoxyl moiety of the ester. Oftenly, the stereoselectivity
The anti-Markovnikovhydration of terminal alkynes to give aldehydes is catalyzed by complexes derived in situ from air-stable [CpRu(eta6-naphthalene)]PF6 (C) and 6-aryl-2-diphenylphosphinopyridines (L). Ligands L are readily available from a modular synthesis. Increasing the size of the ligand C-6 aryl group in the order R = Ph < mesityl < 2,4,6-triisopropylphenyl < (2,4,6-triphenyl)phenyl gave hydration
Efficient and Functional-Group-Tolerant Synthesis of Substituted Furans through the Pd-Catalyzed 5-<i>exo</i>
-<i>dig</i>
Cyclization/Coupling of γ-Acetylenic β-Keto Esters with (Hetero)Aryl Bromides
作者:Agata Kołodziejczyk、Wojciech Chaładaj
DOI:10.1002/ejoc.201800046
日期:2018.6.7
We report an efficient protocol for the synthesis of 2,3,5‐trisubstituted furans through the reaction of readily available γ‐acetylenic β‐keto esters with aryl and heteroaryl bromides. The reaction, which involves a 5‐exo‐dig cyclization, coupling, and isomerization of a double bond, proceeds smoothly with very low catalyst loading (0.1 mol‐%), and shows excellent functional‐group tolerance.