A mild and efficient one-pot visible light-induced method has been developed for the allylic oxidation. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones. The allylic C-H oxidation is relatively simple and predictable, even on a preparative scale, because active species generated at the allylic position are stabilized by the double bond.
Copper-Catalyzed Asymmetric Conjugate Addition of Trialkylaluminium Reagents to Trisubstituted Enones: Construction of Chiral Quaternary Centers
作者:Magali Vuagnoux-d'Augustin、Alexandre Alexakis
DOI:10.1002/chem.200701001
日期:2007.11.26
vinylalane species undergo enantioselective conjugateaddition to a wide range of 2- or 3-substituted enones (cyclopent-2-enones, cyclohex-2-enones, 3-methyl cyclohept-2-enone) in the presence of catalytic amount of copper salt (copper thiophene carboxylate, [Cu(CH3CN)4]BF4 or [CuOTf]2C6H6) and tropos-phosphoramidite-based ligand. Thus, chiral quaternarycenters can be built, with up to 98% ee after rigorous
Practical regioselective halogenation of vinylogous esters: synthesis of differentiated mono-haloresorcinols and polyhalogenated resorcinols
作者:Xiaohong Chen、Xiaoguang Liu、Jenny S. Martinez、Justin T. Mohr
DOI:10.1016/j.tet.2016.02.006
日期:2016.6
A practical and efficient method for the direct, regioselective conversion of vinylogousesters to haloresorcinols is reported. Control of the reaction conditions enables synthesis of either the 4- or 6-haloresorcinol isomers from a common precursor with excellent regiocontrol and high yield. The generality and functional group tolerance of this novel protocol is demonstrated. The utility of this methodology
Addition reaction of arylboronic acids to aldehydes and α,β-unsaturated carbonyl compounds catalyzed by conventional palladium complexes in the presence of chloroform
作者:Tetsuya Yamamoto、Michiko Iizuka、Hiroto Takenaka、Tetsuo Ohta、Yoshihiko Ito
DOI:10.1016/j.jorganchem.2008.12.032
日期:2009.4
Arylboronic acids react with aldehydes and α,β-unsaturatedcarbonylcompounds in the presence of a base and a catalytic amount of a palladium(0) complex with chloroform, affording the corresponding addition products in good yields, and chiral benzhydrol was obtained with up to 43% e.e. using (S,S)-bppm as a ligand. General palladium complexes have no catalytic activity without chloroform. Because chloroform
Formation of Quaternary Chiral Centers by N-Heterocyclic Carbene-Cu-Catalyzed Asymmetric Conjugate Addition Reactions with Grignard Reagents on Trisubstituted Cyclic Enones
The copper‐catalyzedconjugateaddition of Grignard reagents to 3‐substituted cyclic enones allows the formation of all‐carbon chiral quaternary centers. We demonstrate in this article that N‐heterocyclic carbenes act as efficient chiral ligands for this transformation. High enantioselectivities (up to 96 % ee) could be obtained for a variety of substrates.
A new and efficient catalytic asymmetric synthesis of the potent cannabinoid receptor agonist (−)‐CP‐55940 has been developed by using ruthenium‐catalyzed asymmetrichydrogenation of racemic α‐aryl ketones via dynamic kinetic resolution (DKR) as a key step. With RuCl2‐SDPs/diamine [SDPs=7,7′‐bis(diarylphophino)‐1,1′‐spirobiindane] catalysts the asymmetrichydrogenation of racemic α‐arylcyclohexanones