Radical Truce-Smiles reactions on an isoxazole template: Scope and limitations

The use of TiCl₃-HCl as promotor in the radical Truce-Smiles reactions of 2-(((3,5-dimethylisoxazol-4-yl)sulfonyl)oxy)benzenediazonium salts has been investigated in detail. During these reactions the desired Truce-Smiles rearrangement (via an ipso-substitution reaction) is accompanied by the formation of a number of by-products including dihydrobenzo[5,6][1,2]oxathiino[3,4-d]isoxazole 4,4-dioxides, dioxidobenzo[e][1,2]oxathiin-3-yl)ethan-1-ones, anilines and chloroaromatics. Replacing TiCl₃-HCl by Cu(NO₃)₂-Cu₂O as reductant in these reactions was found to afford broadly comparable product distributions. Competition and radical clock experiments also provide an indication of the relative susceptibility of the isoxazole nucleus towards attack by aryl radicals.     

Compositional disorder in trans‐[RhBr0.26Cl0.74H(PMe3)4][B(1,2‐O2C6Br4)]·CH2Cl2

The structure of trans‐(bromo/­chloro)­hy­drido­tetra­kis­(tri‐me­thyl­phos­phine)­rhod­ium(III) bis­(tetra­bromo­pyro­catechol‐ato‐O,O′)­borate dichloromethane solvate, [RhCl_0·74Br_0·26H‐(C₃­H₉­P)₄]­(C₁₂­BBr₈­O₄)·­CH₂Cl₂, is reported. The Rh^III com­plex shows bromine/chlorine compositional disorder with a trans arrangement of the hydride and halide ligands. The anion has approximate D_2d symmetry, with a central spiro‐B atom distorted from regular tetrahedral geometry by the small chelating O—B—O angles.     

Bifurcate, tandem ATRC reactions: towards 2-oxabicyclo[4.3.0]nonane core of eunicellins

Bifurcate, tandem ATRC reactions provide rapid access to 2-oxabicyclo[4.3.0]nonane ring system present in terpenes such as eunicellin.     

Non‐linear,cata‐Condensed,Polycyclic Aromatic Hydrocarbon Materials: A Generic Approach and Physical Properties

A generic approach to the regiospecific synthesis of halogenated polycyclic aromatics is made possible by the one‐ or two‐directional benzannulation reactions of readily available (ortho‐allylaryl)trichloroacetates (the “BHQ” reaction). Palladium‐catalysed cross‐coupling reactions of the so‐formed haloaromatics enable the synthesis of functionalised polycyclic aromatic hydrocarbons (PAHs) with surgical precision. Overall, this new methodology enables the facile mining of chemical space in search of new electronic functional materials.     

Chloro­bis­(tri­phenyl­phosphine)­nickel(I)

Crystals of the title compound, [NiCl(C₁₈H₁₅P)₂], contain one mol­ecule per asymmetric unit with no short intermolecular interactions. This is noteworthy since previous studies have reported that the formally 15‐electron species oligomerizes in the solid state. The nickel(I) centre has a distorted trigonal–planar coordination geometry, the origin of which is suggested to be electronic in nature.     

Three sulfur‐containing diborane(4) compounds

The preparation and structures of three diborane(4) compounds are described. The compound B₂(3,4‐S₂C₄H₂‐1‐S)₂ [2,2′‐bi(1,3,5,2‐tri­thia­borapentalene), C₈H₄B₂S₆] is planar and lies at a crystallographic inversion centre. The amine adducts [B₂(C₃S₅)₂(NHMe₂)₂] [2,2′‐bis­(di­methyl­amino)‐2,2′‐bi(1,3,4,6,2‐tetra­thia­borapentalene‐5‐thione), C₁₀H₁₄B₂N₂S₁₀] and [B₂(1,2‐S₂C₂H₄)₂(NHMe₂)₂]·0.33CH₂Cl₂ [1,2‐bis­(di‐methylamino)‐1,1:2,2‐bis(dimethylenedithioxy)diborane(4) di­chloro­methane solvate, C₈H₂₂B₂N₂S₄·0.33CH₂Cl₂] contain di­methyl­amine ligands bound to each boron in an anti conformation about the B—B bond, with tetrahedral geometry at the B atoms. The crystal structures display a number of S?S interactions, which appear to dictate the packing arrangements.     

A formal synthesis of aflatoxin B2: a Dötz benzannulation approach

A Dötz benzannulation reaction has been utilized in the synthesis of the furo[2,3-b]furan core of aflatoxin B2.     

An approach to oxasteroids

A tandem Dotz-Mitsunobu sequence has been used to prepare the oxasteroid skeleton