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A highly modular 1,4-difunctionalization of 1,3-dienes with bromodifluoroacetamides and sulfinates/amines through a photoinduced palladium-catalyzed radical relay process is described herein. This developed protocol offers a facile and general route to access a variety of value-added CF

A catalyst-free strategy for regioselective hydroxydifluoroalkylation of alkenes with alkyl bromides was developed, affording a series of difluoroalkylated tertiary alcohols in moderate to good yields. This photocatalyst-free protocol shows broad substrate scope under mild conditions. Moreover, mechanistic studies revealed that a newly identified electron donor-acceptor complex is crucial to this transformation.

A novel selective fragmentation of cycloalkanones by NaNO2/HCl has been established. The C-C bond cleavage reaction proceeds smoothly under mild conditions, selectively affording versatile keto acids or oxime acids. The methodology can streamline the synthesis of valuable chiral molecules and isocoumarins from readily available feedstocks.

Electrochemical synthesis of versatile β-keto sulfonyl fluorides is accomplished by radical fluorosulfonylation of vinyl triflates with FSO

Collective total synthesis of five tetrahydroisoquinoline alkaloids including the first total synthesis of (-)-fennebricin A and (-)-renieramycin J has been accomplished. The synthesis features employing a single common amino acid to symmetrically construct the pentacycle of title alkaloids. The palladium-catalyzed arylation of alanine-derived amide developed by Yu was tactically utilized to afford unnatural amino acid building block rapidly and practically. The structure of synthetic (-)-renieramycin M has been confirmed by single crystal X-ray analysis for the first time.

Aromatic enamide and enecarbamate as a novel type of nucleophile in the asymmetric allylation of branched, racemic allylic alcohols to give homoallylic ketones has been described. Enabled by Carreira's chiral Ir (P, olefin) complex, the reactions proceed in good yields with excellent enantioselectivities.

Compounds bearing fluorinated moieties are pervasive in a wide range of pharmaceuticals and agrochemicals. The installation of fluorinated units is a persistently vital task in synthetic chemistry, where facile and manipulable assays are highly demanding. Herein, we establish a general and programmable fluorination strategy for the modular assembly of mono- and difluoromethylarenes through the controllable deprotonation and fluorination of phosphonium ylides. Moreover, the rational combination of the reaction sequence allows the rapid construction of diversified fluorine-containing arenes.

The iridium-catalyzed, Zn(OTf)2 promoted asymmetric allylic amidation of a secondary alcohol derived from tryptamine has been utilized to forge a tetrahydro-β-carboline. Based on this key step, a novel, facile, and enantioselective total synthesis of (−)-geissoschizol was achieved in 10 steps.

Carreira's iridium-(P, olefin) phosphoramidite-based catalytic system that allows asymmetric allyl-allylboronate cross-coupling with high enantioselectivity is reported. This transformation tolerates a large variety of racemic branched allylic alcohols and allylboronate substrates. The utility of the coupling is demonstrated in a concise catalytic asymmetric synthesis of (-)-preclamol.

A simple and efficient method for the meso-functionalization of porphyrin has been developed. Kinetic studies of meso-fluoro-, -chloro-, -bromo-, -iodo-, and -nitro-substituted porphyrins (Ni) with phenol reveal that the reaction undergoes a typical aromatic nucleophilic substitution (SNAr) process. This catalyst-free method can be performed with meso-brominated porphyrins and oxygen-, sulfur-, and carbon-based nucleophiles to achieve a wide variety of meso-substituted porphyrins.

A new class of organic dyes based on triazatruxene have been designed and synthesized for dye-sensitized solar cells. The photoelectronic properties of these donor-π-acceptor dyes can be tuned by changing π-conjugated linkers. The best performance was found for triazatruxene dye TD1, wherein, with thiophene as the conjugated linker and cyanoacrylic acid as the acceptor, a power conversion efficiency up to 6.10% was achieved.

The synthesis of a directly linked zinc chlorin dimer was first achieved by a facile and efficient oxidative coupling of zinc chlorin monomers with phenyliodine bis(trifluoroacetate) (PIFA). The reaction shows high regioselectivity at the 20-position near the hydrogenated pyrrole ring producing selective dichlorin in 74% yield.

An efficient and metal-free oxidative method was reported for synthesis of triply linked diporphyrins with 2.5 equiv of phenyliodine bis(trifluoroacetate) (PIFA). This reaction showed high selectivity for Zn(II) porphyrins and had been successfully applied in the synthesis of a novel triply-singly interlacedly linked porphyrin array with lower energy gap.

A highly efficient, metal-free, and divergent method for the synthesis of 3,4-dihydropyridin-2-one and pyrrolidin-2-one Clausena alkaloids and their analogs is reported. While the oxirane-containing enamides underwent the TFA-mediated 6-endo-enamide-epoxide cyclization reaction in Bu(t)OH to produce homoclausenamides, an unprecedented nucleophilic reaction occurred at the alpha-carbon of enamides in water to yield 5-endo-enamide-epoxide cyclization products in excellent yields. The reversal of nucleophilicity of enamides in intramolecular cyclization is discussed in terms of steric and electronic effects of the oxirane-containing enamides.

A new approach to the synthesis of meta-substituted enantiopure inherently chiral calix[4]arenes by introducing L-Boc-proline as dual functions of the chiral auxiliary has been described. Moreover, the absolute configurations of the enantiomers were determined by CD spectra, X-ray crystallographic analysis, and the chemical derivative method.

[Structure: see text] Catalyzed by the Rhodococcus erythropolis AJ270 whole cell catalyst, the O-benzylated beta-hydroxy alkanenitriles underwent remarkably high enantioselective biotransformations, whereas the biotransformations of free beta-hydroxy alkanenitriles gave very low enantioselectivity. The easy manipulations of O-protection and O-deprotection, excellent chemical and enantiomeric yields of biotransformations, along with the scalability render this enzymatic transformation attractive and practical for the synthesis of highly enantiopure beta-hydroxy alkanoic acids and their amide derivatives.

[reaction: see text] Under acidic conditions, a fluorescence-quenching process of 1 induced by selective binding of alkali metal ions was discovered. The mechanism of this new process involves alkali metal ion-induced deprotonation of the ammonium ion to trigger resumption of a fluorescence-quenching PET process.

An efficient rhenium-catalyzed site-switchable addition of indoles to terminal alkynes is described. A variety of bisindolylalkane derivatives are expeditiously synthesized in high yields with excellent regioselectivity. Preliminary mechanistic study sheds light on the observed regiodivergent addition.

A new tweezer-like receptor containing a pentiptycene unit and a benzene ring linked by two crown ether chains has been synthesized. It could form stable complexes with paraquat derivatives with different functional groups in solution and in the solid state. It was found that the complexes dissociated upon two one-electron reduction of the bipyridinium ring. Moreover, binding and release of the guest molecules could also be easily controlled by the addition and removal of potassium ion.

Large methylazacalix[n]pyridines (n = 6-9) were synthesized effectively from the Pd-catalyzed macrocyclic fragment coupling reactions between alpha,omega-dibrominated and alpha,omega-diaminated linear oligomers. As macrocyclic host molecules, they formed a 1:1 complex with fullerenes C(60) and C(70) with association constants ranging from 3 x 10(4) to 1 x 10(5) M(-1).

A stepwise fragment coupling reaction starting with substituted dichlorotriazine and resorcinol derivatives gave rise to thermodynamically favored 1,3-alternate tetraoxacalix[2]arene[2]triazines and kinetically controlled flattened partial cone tetraoxacalix[2]arene[2]triazines. The flattened partial cone conformer, which was stable due to the steric effect, converted into the 1,3-alternate conformer via ether bond cleavage upon treatment with an inorganic base.

[structure: see text] Owing to the electronic nature of the bridging nitrogen atoms which can adopt different hybridizations and form various conjugations with the adjacent pyridine(s), methylazacalix[4]pyridine underwent conformation and cavity preorganization to highly selectively bind the Zn(2+) ion. Rigidification and coplanarity of the macrocyclic ring led to a great enhancement of fluorescence of the intrinsic fluorescent host molecule.