Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans

• Cornelia Chizzali and
• Ludger Beerhues

Beilstein J. Org. Chem. 2012, 8, 613–620, doi:10.3762/bjoc.8.68

• Cornelia Chizzali Ludger Beerhues Institut für Pharmazeutische Biologie, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106 Braunschweig, Germany 10.3762/bjoc.8.68 Abstract Biphenyls and dibenzofurans are the phytoalexins of the Pyrinae, a subtribe of the plant family Rosaceae. The

• Pyrinae correspond to the long-recognized Maloideae. Economically valuable species of the Pyrinae are apples and pears. Biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. The inducible defense compounds were also produced in cell suspension cultures

• after treatment with biotic and abiotic elicitors. The antimicrobial activity of the phytoalexins was demonstrated. To date, 10 biphenyls and 17 dibenzofurans were isolated from 14 of the 30 Pyrinae genera. The most widely distributed compounds are the biphenyl aucuparin and the dibenzofuran γ

Bromine–lithium exchange: An efficient tool in the modular construction of biaryl ligands

• Laurence Bonnafoux,
• Frédéric R. Leroux and
• Françoise Colobert

Beilstein J. Org. Chem. 2011, 7, 1278–1287, doi:10.3762/bjoc.7.148

• the modular synthesis of various polysubstituted biphenyls such as bis(dialkylphosphino)-, bis(diarylphosphino)- and dialkyl(diaryl)phosphinobiphenyls. All permutations of substituents at the ortho positions of the biphenyls are possible. In a similar manner, one can gain access to monophosphine

• or ligands, which are especially required for the coupling of deactivated or sterically hindered substrates. Our group is developing new methods towards the synthesis of highly functionalized atropisomeric biphenyls [23][24][25][26][27][28][29][30][31][32]. We seek to perform their synthesis (a) in a

• ). Results and Discussion Regioselective bromine–lithium exchange on polybrominated biphenyls Our group recently reported the efficient coupling of organolithium intermediates with arynes, the so-called "ARYNE coupling" [25][31][36]. This protocol is based on the formation of a thermodynamically stable

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

• Norio Shibata,
• Andrej Matsnev and
• Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

• work, it was stressed that the purity of trifluoromethanesulfinate salts is an essential factor for the success of this reaction; low purity of the latter decreased the yield of the desired sulfonium salt. Starting from biphenyls, the method is applicable to the synthesis of Umemoto’s type reagents

Solvent-free and time-efficient Suzuki–Miyaura reaction in a ball mill: the solid reagent system KF–Al₂O₃ under inspection

• Franziska Bernhardt,
• Ronald Trotzki,
• Tony Szuppa,
• Achim Stolle and
• Bernd Ondruschka

Beilstein J. Org. Chem. 2010, 6, No. 7, doi:10.3762/bjoc.6.7

• pH measurements of aqueous suspension of the pure aluminas. Investigating the influence of different SRS, the Pd(OAc)2-assisted Suzuki–Miyaura coupling of phenylboronic acid (1) with different aryl bromides 2 furnishing p-substituted biphenyls 3 (Scheme 1) was chosen. Reactions were performed in a

• Al2O3 was shown to act solely as a base in the investigated cross-coupling to biphenyls, the resulting yields were inferior to the yield required for application in synthesis. To increase the basicity of the SRS KF-loaded aluminas, SRS1a–3a, which were promising for application in the Suzuki–Miyaura

Control of stilbene conformation and fluorescence in self-assembled capsules

• Mark R. Ams,
• Dariush Ajami,
• Stephen L. Craig,
• Jye-Shane Yang and
• Julius Rebek Jr

Beilstein J. Org. Chem. 2009, 5, No. 79, doi:10.3762/bjoc.5.79

• depicted in Figure 1A, the square prisms are twisted by about 45° along their long axes. A typical aromatic guest such as benzene fits best when it is nestled diagonally in a prism’s space. Accordingly, the aromatic rings of longer molecules such as biphenyls and stilbenes cannot be coplanar in their