Origin of stereoselectivity in an isothiourea catalyzed Michael addition reaction of aryl ester with vinyl disulfone

The origin of stereoselectivity in an isothiourea-catalyzed addition reaction of aryl ester with vinyl disulfone was explored for the first time.

Aryloxide-Promoted Catalyst Turnover in Lewis Base Organo­catalysis

This short review highlights select examples of enantioselective Lewis base promoted reactions that use tertiary amine (cinchona alkaloids, isothioureas, and DMAP/PPY derivatives) or NHC catalysts and employ aryloxide-promoted catalyst turnover from an acyl ammonium or azolium intermediate. This review focuses on the range of strategies that have been developed within this area, and discusses their evolution and context.1 Introduction2 Phenols as Additives To Promote Catalyst Turnover2.1 NHC Catalysis with α-Functionalised Aldehydes and Phenols2.2 Enantioselective Fluorination with Aryloxide-Promoted Catalyst Turnover3 In Situ Catalytic Generation Of Aryloxide3.1 Aryloxide-Promoted Turnover Generated from an Electrophilic Polyhalogenated Quinone: Overview3.2 Aryloxide-Promoted Catalyst Turnover Generated from an α-Aryl­oxyaldehyde or Aryl Ester Starting Material: Overview4 Summary and Outlook

Synthesis and Characterization of a Methanofullerene-4-Fluoro-α-Cyanostilbene Dyad as a Potential Acceptor for Organic Solar Cells

ABSTRACTA series of fluorine appended highly conjugated fullerenes were prepared containing fluoro-α-cyanostilbene and aryl ester units. These modified PCBM dyads are fully characterized by NMR, Mass spectrometry, UV-vis, and cyclic voltammetry (Figures 1-4). It was found that the presence of fluoro-α-cyanostilbenes and esters affects the cyclic voltammetry and absorption in the UV-Vis region. The PCBA modified fullerenes significantly influences the HOMO-LUMO energy and wide absorption compared to PCBM.

Crystal structure of 2-(4-chlorophenyl)-2-oxoethyl 3-bromobenzoate

2-(4-Chlorophenyl)-2-oxoethyl 3-bromobenzoate, C15H10BrClO3, was synthesized in a single-step reaction by condensation of 3-bromobenzoic acid with 2-bromo-1-(4-chlorophenyl)ethanone in dimethylformamide in the presence of triethylamine as a catalyst. The structure consists of an aryl ketone moiety linked to an aryl ester unit by a methylene group. Both units are reasonably planar (r.m.s. deviations of 0.119 and 0.010 Å for the aryl ketone and aryl ester units, respectively) and are almost orthogonal, with an angle of 88.60 (3)° between them. In the crystal, molecules form five separate sets of inversion dimers. Three of these are generated by two C—H...O interactions and a C—H...Br contact, and form chains alongcand along theabcell diagonal. In addition, two inversion-related π–π stacking interactions between like aryl rings again form chains of molecules but in this instance along thebcdiagonal. These contacts generate infinite layers of molecules parallel to (011) and stack the molecules along thea-axis direction.

Dimethyl 2-nitrobiphenyl-4,4′-dicarboxylate

The title compound, C16H13NO6, exhibits a biphenyl unit with a dihedral angle between the two aryl rings of 56.01 (5)°. The two ester groups vary slightly from planarity, with aryl–ester dihedral angles of 4.57 (5) and 16.73 (5)°. The nitro group is turned from the aromatic unit with an aryl–nitro dihedral angle of 48.66 (4)°. In the crystal, molecules are connected by weak C—H...O interactions, forming a three-dimensional network.