A highly efficient construction of chiral γ-substituted α-allyl-α,β-butenolides with up to >99% enantiomeric excess from readily available allylic ynoates is realized. In this asymmetric gold catalysis, the cationic gold(I) catalyst featuring a bifunctional phosphine ligand enables a four-step cascade which permits the conversion of a diverse array of allylic ynoates into valuable chiral α,γ-disubstituted α,β-butenolides.
The selective fusions with pyrene derivative to the rim and flank bonds of corannulene generated 4 and 7, respectively, which underwent a Scholl reaction to provide novel distorted PAHs CORA-1 and CORA-2, consisting of corannulene and dibenzocoronene units with different connections between them. The studies revealed that the properties of these PAHs are highly dependent on the fusing positions of corannulene.
A redox neutral radical-relay cobalt-catalyzed intramolecular C–H fluorination of N-fluoroamides featuring the in situ formed cobalt fluorides as the latent radical fluorinating agents is reported. Moreover, the reactivity of such a cobalt catalysis could be diverted from C–H fluorination to amination by engineering substrates’ conformational flexibility. Preliminary mechanistic studies (UV–vis spectroscopy, cyclic voltammetry studies and DFT calculations, etc.) support the reaction proceeding a redox neutral radical-relay mechanism.
We present a novel Cu-catalyzed aromatic metamorphosis of 3-aminoindazoles via oxidative cleavage of two C–N bonds of 3-aminoindazoles. This unprecedented reactivity of 3-aminoindazoles allows one to forge diverse nitrile-containing triphenylenes in decent yields via generation of the cyano group in situ. The current study reveals that 3-aminoindazoles could be harnessed as radical precursors via oxidative denitrogenation, the reaction mechanism of which was supported by density functional theory calculations.
The many manifestations of aromaticity have long fascinated both experimentalists and theoreticians. Due to their degenerate half-filled MOs, triplet [n]annulenes with 4n π-electrons are also aromatic, but the degree of their stabilization has been difficult to quantify. The isomerization stabilization energy (ISE) method has been applied to evaluate the triplet aromaticity. The reliability of this approach is indicated by the strong correlation of the ISE results with NICS(1)zz, a magnetic indicator of triplet state aromaticity.
P-Arylation in water has been developed via cross-coupling of aryl halides with diphenylphosphine oxide (Ph2P(O)H) and (RP)-(−)-menthyl benzylphosphinate catalyzed by NiCl2·6H2O/Zn under relatively mild conditions.