共轭烯烃的共轭极化势

Based on the conjugated polarization theory,it is expressed as the conjugated polarizability potential （CPP）that the discrepancy between the average electrostatic energy of dipolar state and the electrostatic energy of non-polar state in the conjugated polarizability procedure for the conjugated alkenes. The correlation between CPP and the energy of ultraviolet absorption maximum,and the correlation between the energy of frontier molecular orbital obtained by ab initio calculation of quantum chemistry and the energy of ultraviolet absorption maximum have been carried out for the conjugated alkenes. Both correlation equations show a similar estimated precision. Further, the contribution of alkyl polarizability effect to the stability of dipolar state for the alkyl substituted alkenes with the effective polarizability effect index（PEI（ef））was quantified. Relating the above two parameters CPP and PEI（ef）to the energy of ultraviolet absorption maximum of the substituted alkenes in a two-parameter expression with a good prediction ability was obtained:v=1.1746+5.0187CPP-0.43204PEI （ef）,R=0.9995,s=0.0403,F=10853.28,n=23. The investigated results also indicate that it is less effective to reduce the energy of ultraviolet absorption maximum by means of increasing the alkyl substituent groups than lengthening the conjugated backbone chain in the conjugated alkenes.     

Trinuclear Gold-Catalyzed 1,2-Difunctionalization of Alkenes

Activated alkyl halides have been extensively explored to generate alkyl radicals with Ru- and Ir- photocatalysts for 1,2-difunctionalization of alkenes, but unactivated alkyl bromides remain challenging substrates due to their strong reduction potential. Here we report a three-component 1,2-difunctionalization reaction of alkenes, unactivated alkyl bromides and nucleophiles (e.g., amines and indoles) using a trinuclear gold catalyst [Au₃(tppm)₂](OTf)₃. It can achieve the 1,2-aminoalkylation and 1,2-alkylarylation readily. This protocol has a broad reaction scope and excellent functional group compatibility (>100 examples with up to 96 % yield). It also affords a robust formal [2+2+1] cyclization strategy for the concise construction of pyrrolidine skeletons under mild reaction conditions. Mechanistic studies support an inner-sphere single electron transfer pathway for the successful cleavage of inert C−Br bonds.     

Synthesis of hept-6-en-2,4,5-triols and hept-6-en-2,3,5-triols

In a systematic effort to establish the relative as well as absolute configurations of two natural products isolated from Asomycete Daldinia concentrica, four independent (non-antipodal) diastereomers of hept-6-en-2,4,5-triol, the structure previously proposed for the natural products, were synthesized in enantiopure forms through a chiral-pool route and their optical rotation as well as NMR data were recorded. Although these four synthetic isomers cover all possible relative configurations the originally assigned triol may have, none of them gave spectroscopic data compatible with those reported for the natural products. Similar negative results were also obtained with a group of four non-antipodal diastereomers of hept-6-en-2,3,5-triol. The genuine structures of the natural products are therefore to be re-assigned.     

Co-immobilized formate anion and palladium on a polymer surface: a novel heterogeneous combination for transfer hydrogenation

A novel heterogeneous combination of a formate reagent and palladium catalyst co-immobilized on a resin support has been developed and shown to be highly efficient and recyclable for transfer hydrogenation of alkenes, imines, nitroarenes and 1,2-dicarbonyl compounds.     

Reactivity in the upper limits of the reduction potential in solution: arene dianion intermolecular carbolithiation of alkenes

Lithium salts of dianions derived from arenes of high reduction potential (biphenyl, naphthalene) can carbometallate terminal alkenes (propene, isobutene) in an intermolecular fashion, affording partially dearomatized alkylated aryl anions, which are susceptible to further functionalization by electrophilic capture. This form of reactivity, specific of the arene dianion, deviates from the typical alkali metal-like reactivity displayed by these complexes, affording in most cases regio- and stereocontrolled products. Simple semiempirical calculations (PM3) help predicting the regiochemical outcome of this reaction, where some of the most inexpensive organic starting materials are involved.     

Titanocene-catalyzed double silylation of dienes and aryl alkenes with chlorosilanes

Double silylation of 1,3-butadienes with chlorosilanes was found to proceed by using titanocene dichloride as the catalyst in the presence of ⁿBuMgCl, giving rise to 1,4-disilylated 2-butenes in good yields. Aryl substituted alkenes also afforded 1,2-disilylated products under similar conditions.     

Synthesis of stereodefined 1-aryl(heteroaryl) substituted 1,2-bis(2-bromopyridin-3-yl)ethenes by selective tandem Suzuki-Miyaura cross-coupling reactions

A protocol for the synthesis of stereodefined 1-aryl(heteroaryl) substituted 1,2-bis(2-bromopyridin-3-yl)ethenes by tandem Suzuki-Miyaura cross-coupling reactions and an example of convention into 5-phenyl-1,10-phenanthroline are described.     

Ligand-Enabled NiII-Catalyzed Hydroxylarylation of Alkenes with Molecular Oxygen

The use of molecular oxygen as the terminal oxidant in transition metal catalyzed oxidative process is an appealing and challenging task in organic synthetic chemistry. Here, we report a Ni-catalyzed hydroxylarylation of unactivated alkenes enabled by a β-diketone ligand with high efficiency and excellent regioselectivity employing molecular oxygen as the oxidant and hydroxyl source. This reaction features mild conditions, broad substrate scope and incredible heterocycle compatibility, providing a variety of β-hydroxylamides, γ-hydroxylamides, β-aminoalcohols, γ-aminoalcohols, and 1,3-diols in high yields. The synthetic value of this methodology was demonstrated by the efficient synthesis of two bioactive compounds, (±)-3′-methoxyl citreochlorol and tea catechin metabolites M4.     

Acetonitrile-dependent oxyphosphorylation: A mild one-pot synthesis of β-ketophosphonates from alkenyl acids or alkenes

An efficient one-pot synthesis of β-ketophosphonates has been developed, via the reaction of α,β-alkenyl carboxylic acids or alkenes with H-phosphonates and air oxygen, catalyzed by CuSO₄·5H₂O in CH₃CN. CH₃CN plays a decisive role, probably by forming an active oxygen complex [(MeCN)_nCu^II-O-O·].