Photocatalytic Site-Selective Cascade Radical Addition of Biaryl Ynones for the Construction of Spiro-and Fused Carbon Rings

Functionalized free radical addition/cyclization reactions represent an efficient way for introducing new functionality or coupling fragments to molecules.Ynones are good regional selectivity radical acceptors in organic synthesis,and many of bio-relevant cyclic compounds could be easily obtained by direct radical cyclization reaction.Here,we report a photocatalytic cascade radical addition of biaryl ynones,for the divergent synthesis of privileged carbon cycles.Additionally,further transformation of the multi-functional group product into a variety of other derivatives demonstrates the synthetic value of this developed method.

Pd-catalyzed asymmetric carbonyl alkynylation:Synthesis of axial chiral ynones

Ynones are important skeletons in bioactive molecules and valuable building blocks for organic synthesis,thus great efforts have been devoted to their preparation.While,introducing prochiral substrates to construct ynones bearing a chiral framework is unrealized to date.Herein,we reported the first example of Pd/SOP-catalyzed asymmetric carbonylative alkynylation via a non-classical carbonylative Sonogashiratype approach(acyl-Pd(Ⅱ)species generated from nucleophiles).By using cyclic diaryliodonium salts as prochiral substrates,various axial chiral ynones with good functional group tolerance(39 examples),satisfied yields(71%-96%)and excellent enantioselectivities(generally 94%-99%ee)were produced.Synthesis of bioactive compounds,scale-up experiment and useful transformations were also conducted to demonstrate the utility of this process.

Asymmetric Aminations and Kinetic Resolution of Acyclic α-Branched Ynones

An efficient method for asymmetric synthesis of acyclic α-tertiary amine derivatives has been achieved through enantioselective aminations of α-branched ynones with azodicarboxylates enabled by chiral phosphoric acid catalysis.Moreover,kinetic resolution of racemic starting material was realized under these conditions,which gave access to valuable enantioenriched α-substituted ketones.

Multisubstituted pyrazole synthesis via[3+2]cycloaddition/rearrangement/N-H insertion cascade reaction of α-diazoesters and ynones

The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)_(3) as the catalyst are described.A series of 4-substituted pyrazoles were obtained via [3+2] cycloaddition,1,5-ester shift,1,3-H shift,and N-H insertion process.Deuterium labelling experiments,kinetic studies and control experiments were carried out for the rationalization of the mechanism.

Using Pd-salen complex as an efficient catalyst for the copper-and solvent-free coupling of acyl chlorides with terminal alkynes under aerobic conditions

The palladium-salen complex palladium(Ⅱ) N,N'-bis{[5-(triphenylphosphonium)-methyl]salicylidene}-1,2-ethanediamine chloride was found to be a highly active catalyst for the copper- and solvent-free coupling reaction of terminal alkynes with different acyl chlorides in the presence of triethylamine as base,giving excellent ynones under aerobic conditions.

Ynone(炔酮或炔酯)在自由基串联反应中的应用

Ynone属于多官能团化合物,在有机合成中有着重要的价值。综述了近十年来Ynone在自由基串联反应中的应用,并对已有的反应策略进行了分类和讨论。

Synthesis, structure, and catalytic activity of rare-earth metal amides with a neutral pyrrolyl-functionalized indolyl ligand

The reactions of neutral pyrrolyl-functionalized indole with rare-earth metal amides [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 produced the rare-earth metal complexes [(Me3Si)2N]2RE([η1:μ-η2-3-(2-(N–CH3)C4H3NCH=N–CH2CH2)C8H5N])(μ-Cl)Li(THF)(RE = Er, Y) having indolyl ligand η1 bonded to rare-earth metal ion and η2 bonded to lithium ion. The catalytic activities of these lanthanide amido complexes for addition of terminal alkynes to aromatic nitriles were explored. Results reveal that these complexes displayed a good catalytic activity for the addition reaction under mild conditions.