Catalytic Decarboxylative Alkenylation of Enolates

Synthesis of fluoroolefin derivatives by nickel(II)-catalyzed trifluorovinylation and 1,2,2-trifluoroethylation of cinnamyl alcohols

Nickel(II)-catalyzed regioselective trifluorovinylation and 1,2,2-trifluoroethylation of allyl alcohols with trifluorovinyl reagents were performed. The reaction of (E)-3-phenylprop-2-en-1-ol and trifluorovinylzinc bromide (TFVZ) afforded 1,2,2-trifluorovinyl diene in moderate to high yields. The reaction of (E)-3-phenylprop-2-en-1-ol and trifluorovinyl trimethylsilane (TFVTMS) resulted in the novel nucleophilic addition product 1,1,2-trifluoroethoxy aryl olefin.

Synthetic Studies on the Synthesis of Toxicodenane A and 8,11-epi-Toxicodenane A

The diverse synthesis of oxatricyclotridecanes and oxatricyclododecanes, which are the core structures of toxicodenane A and its skeletal analogues, via a unified manner is presented. The stereochemistry at the bridgehead position of the oxa-bridged bicycle could be efficiently controlled through a diastereoselective anti- and syn-Grignard allylation reaction by appropriately tuning the reaction conditions such as the solvent, the counterion of the Grignard reagent, the substrate, or a combination of these. The ring size could be precisely elaborated via a Lewis acid-mediated intramolecular transacetalation and Prins cyclization cascade reaction by varying the steric hindrance of olefin moiety. Namely, substrates bearing a terminally unsubstituted olefinic functionality afforded oxatricyclotridecanes with an overwhelming preference, while those bearing a dimethyl-substituted olefinic group produced exclusively oxatricyclododecanes. The wide utility and generality of the above key transformations are highlighted by the applications in the unified synthesis of (±)-toxicodenance A, (+)-toxicodenane A, (+)-8,11-epi-toxicodenane A, and other oxatricyclic cores with different stereochemistries and ring sizes.

Palladium-Catalyzed Decarboxylative O-Allylation of Phenols with γ-Methylidene-δ-valerolactones

A novel Palladium-Catalyzed decarboxylative O-allylation of phenols was developed, in which a γ-methylidene-δ- valerolactone (GMDVs) was found to be an efficient and selective allylation reagent, affording the target allyl phenyl...

Enantioselective Total Synthesis and Absolute Configuration Assignment of (+)-Toxicodenane A

We present the first enantioselective total synthesis and absolute configuration assignment of (+)-toxicodenane A via a nine-step sequence from the readily available material. The synthesis features a desymmetric enantioselective reduction of 2,2-disubstituted 1,3-cyclohexanedione for the synthesis of a chiral 2,2-disubstituted 3-hydroxy cyclohexanone building block, a highly diastereoselective Grignard reaction for the incorporation of an allyl group, and a Lewis acid-mediated intramolecular transacetalation and Prins cascade reaction for the construction of oxa-bridged bicyclic rings.

Palladium-Catalyzed Direct α-Arylation of Indane-1,3-dione to 2-Substituted Indene-1,3-diones

A straightforward and feasible palladium-catalyzed direct α-arylation of indane-1,3-dione to 2-substituted aryl/heteroaryl indene-1,3-diones has been disclosed for the first time. Optimization of reaction conditions identified ^tBu-XPhos as a preferred ligand for the bis(acetonitrile)dichloropalladium(II) catalyst. A broad spectrum of aryl iodides and aryl triflates containing electron-donating, electron-withdrawing, and sterically hindered substituents gave an excellent yield for the quick access α-arylated 1,3-diones library.

Palladium-catalyzed chemoselective synthesis of indane-1,3-dione derivatives via tert-butyl isocyanide insertion

A simple and efficient strategy for the synthesis of indane-1,3-dione derivatives through a palladium(0)-catalyzed reaction incorporating tert-butyl isocyanide has been developed. In addition, by applying this protocol as the key step, indenopyrazole derivatives can be easily synthesized in high yields in a one-pot procedure. This methodology is tolerant of a wide range of substrates and applicable to library synthesis.

Decarboxylative Csp3–Csp3 coupling for benzylation of unstable ketone enolates: synthesis of p-(acylethyl)phenols

A new decarboxylative C_sp3–C_sp3 coupling approach for the benzylation of ketone enolates has been developed.

Domino Michael-aldol annulations for the stereocontrolled synthesis of bicyclo[3.3.1]nonane and bicyclo[3.2.1]octane derivatives

One-pot synthesis of bicyclo compounds from cycloalkane-1,3-diones and enals.

Regioswitchable Palladium-Catalyzed Decarboxylative Coupling of 1,3-Dicarbonyl Compounds

A palladium-catalyzed chemo- and regioselective coupling of 1,3-dicarbonyl compounds via an allylic linker has been developed. This reaction, which displays broad substrate scope, forms two C-C bonds and installs two all-carbon quaternary centers. The regioselectivity of the reaction can be predictably controlled by utilizing an enol carbonate of one of the coupling partners.

Rapid access to spirocyclized indolenines via palladium-catalyzed cascade reactions of tryptamine derivatives and propargyl carbonate

We report the intermolecular palladium-catalyzed reaction of tert-butyl propargyl carbonate with tryptamine derivatives or other indole-containing bis-nucleophiles. The reaction proceeds under mild conditions and with low catalyst loadings to afford novel spiroindolenine products in good to high yields.