New Method for Preparation of Coumarins and Quinolinones via Pd-Catalyzed Intramolecular Hydroarylation of C−C Triple Bonds

A new and general method has been developed for preparation of coumarins and quinolinones by intramolecular hydroarylation of alkynes. Various aryl alkynoates and alkynanilides undergo fast intramolecular reaction at room temperature in the presence of a catalytic amount of Pd(OAc)2 in a mixed solvent containing trifluoroacetic acid (TFA), affording coumarins and quinolinones in moderate to excellent yields with more than 1000 turnover numbers (TON) to Pd. The methodology proved to tolerate a number of functional groups such as Br and CHO. On the basis of isotope experiments, a possible mechanism involving ethynyl chelation-assisted electrophilic metalation of aromatic C−H bonds by in-situ generated cationic Pd(II) species has been discussed. Also the involvement of vinylcationic species has been suggested

Pd-Catalyzed Selective Addition of Heteroaromatic C−H Bonds to C−C Triple Bonds under Mild Conditions

Simple heteroarenes such as pyrroles and indoles undergo addition reactions to C−C triple bonds in the presence of a catalytic amount of Pd(OAc)2 under very mild conditions, affording cis-heteroarylalkenes in most cases. The cleavage of aromatic C−H bonds is the possible rate-determining step in CH2Cl2, and the addition of heteroaromatic C−H bonds to C−C triple bonds is in a trans-fashion

Molecular cloning and functional analysis of a flavanone 3-hydroxylase gene from blueberry

<p><i>Vaccinium corymbosum</i> (blueberry) is touted as a superfood with numerous health benefits due to its high levels of flavonoids. Flavanone 3-hydroxylase (F3H) is a key regulatory enzyme of the flavonoid pathway. In this study, we cloned the full-length cDNA of <i>F3H</i> (designated <i>VcF3H</i>) from young blueberry leaves using rapid amplification of cDNA ends (RACE). The cDNA contained a 1080-bp open reading frame that encoded a 359-amino acid protein. The deduced VcF3H protein showed high similarities to other plant F3Hs. Conserved amino acid motifs required for ferrous iron binding (HXD) and 2-oxoglutarate binding (RXS) were identified in VcF3H, VcFLS (flavonol synthase), and VcANS (anthocyanidin synthase). Quantitative RT-PCR analysis demonstrated that <i>VcF3H</i> was expressed in all tissues tested, with particularly high expression in young leaves, fruits (pink and blue), and stems. Anthocyanins accumulated mainly in fruits, whereas flavonols were found mainly in leaves and stems. Furthermore, the expression pattern of <i>VcF3H</i> was similar to that of <i>VcCHS</i>, <i>VcDFR</i>, and <i>VcANS</i> in various tissues. Heterologous expression of <i>VcF3H</i> in <i>Arabidopsis thaliana</i> increased the anthocyanin content in leaves, but did not affect the flavonol content. Thus, <i>VcF3H</i> seems to be involved in anthocyanin synthesis in the flavonoid biosynthetic pathway when ectopically expressed in <i>Arabidopsis</i>.</p

Novel Pd(II)- and Pt(II)-Catalyzed Regio- and Stereoselective <i>trans</i>-Hydroarylation of Alkynes by Simple Arenes

Efficient trans-hydroarylation of alkynes by simple arenes has been realized regio- and stereoselectively at room temperature in the presence of Pd(II) or Pt(II) catalysts and a mixed solvent containing trifluoroacetic acid (TFA). Various arenes undergo trans-hydroarylation selectively across terminal and internal C−C triple bondsincluding those conjugated to CHO, COMe, CO2H, and CO2Et groups, affording kinetically controlled cis-arylalkenes predominantly in most cases, especially, in good yields for electron-rich arenes and activated alkynes. The formation of arene/alkyne 1/2 or 2/1 adducts as side products is dependent on the arenes' and alkynes' substituents, which can be suppressed in some cases by changing the catalyst, catalyst concentration, and reaction time. The Pt(II) system, PtCl2/2AgOAc/TFA, shows lower catalytic activity than Pd(OAc)2/TFA, but higher selectivity, giving higher yields of adducts at the same conversion. On the basis of several isotope experiments and control reactions, a possible mechanism involving electrophilic metalation of aromatic C−H bonds by in-situ-generated cationic Pd(II) and Pt(II) species leading to intermolecular trans-arylpalladation to alkynes has been discussed

Additional file 4 of Identification of ARF family in blueberry and its potential involvement of fruit development and pH stress response

Additional file 4: Figure S1. Phylogenetic analysis of ARF genes in blueberry and Arabidopsis. The CDS sequences of AtARFs were downloaded from the TAIR website (www.arabidopsis.org). A maximum likelihood tree was generated with the CDS sequences of the ARF genes using the MEGA7 software

Additional file 1 of Identification of ARF family in blueberry and its potential involvement of fruit development and pH stress response

Additional file 1: Table S1. Characterization of the ARF gene familyin blueberry

Additional file 5 of Identification of ARF family in blueberry and its potential involvement of fruit development and pH stress response

Additional file 5: Figure S2.  Transcript profiling of the potential targets or downstream genes of VcARFs. (A) Transcript profiling during fruit development (five stages: pad, cup, mg, pink, ripe). (B-C) Transcript profiling in response to different pH conditions (pH4.5 and pH6.5) in pH-sensitive Vaccinium corymbosum  (B) and pH-tolerant Vaccinium arboretum (C). The color scale beside the heat map indicates gene expression levels, low transcript abundance indicated by blue color and high transcript abundance indicated by red color. The heatmaps were generated using the software TBtools (Version 1.098689, https://github.com/CJ-Chen/TBtools/releases)

Additional file 2 of Identification of ARF family in blueberry and its potential involvement of fruit development and pH stress response

Additional file 2: Table S2. Identities of VcARF gene pairs and their corresponding Ka/Ks values

Additional file 6 of Identification of ARF family in blueberry and its potential involvement of fruit development and pH stress response

Additional file 6. Raw data for qRT-PCR investigation during fruit development

Additional file 3 of Identification of ARF family in blueberry and its potential involvement of fruit development and pH stress response

Additional file 3: Table S3. Primers used in the stud