ChemInform Abstract: Towards Diversity-Oriented Stereoselective Syntheses of Biaryl- or Bis(aryl)metal-Containing Medium Rings.

Abstract

Experimental Techniques and Apparatus Except as otherwise indicated, reactions were carried out under argon with dry, freshly distilled solvents. Tetrahydrofuran was distilled from sodium/benzophenone ketyl. Anhydrous 2-methyltetrahydrofuran (Aldrich, racemic) was stored over activated molecular sieves. Dichloromethane was distilled from calcium hydride. n-BuLi in hexane (Aldrich) and t-BuLi in pentane (Aldrich) were titrated with 1,10phenanthroline and anhydrous 2-butanol before use. All other reagents were purif ied in accordance with the instructions in “Purif ication of Laboratory Chemicals” or used as obtained from commercial sources. Yields refer to chromatographically and spectroscopically pure compounds. All reactions were monitored by thin layer chromatography (TLC) using glass plates precoated with E. Merck silica gel 60 F254 or aluminium oxide 60 F254. Visualization was by the quenching of UV f luorescence (λmax=254nm) or by staining with ceric ammonium molybdate or Dragendorff ’ s reagent (0.08% w/v bismuth subnitrate and 2% w/v KI in 3M aq. AcOH). Retention factors (Rf) are quoted to 0.01. Melting points were obtained using a Mel-Temp II melting point apparatus and are uncorrected. Infrared spectra were recorded either as a thin f ilm between NaCl plates or as a KBr disc on a Nicolet 5PC FT-IR spectrometer with internal referencing. Absorption maxima (νmax) are reported in wavenumbers (cm) and the following abbreviations are used: w, weak; m, medium; s, strong; br, broad. Proton magnetic resonance spectra were recorded on Varian Mercury400 (400MHz), Bruker Avance DMX500 (500MHz), and Varian Unity/Inova500 (500MHz) spectrometers. Proton assignments are supported by H-H COSY, HMQC, NOESY and GOESY spectra where necessary. Chemical shifts (δH) are quoted in ppm and are referenced to tetramethylsilane (internal). Coupling constants (J) are reported in Hertz to the nearest 0.5Hz. Data are reported as follows: chemical shift, integration, multiplicity [br, broad; s, singlet; d, doublet; t, triplet; q, quartet; qui, quintet; sept, septet; m, multiplet; or as a combination of these (e.g. dd, dt, etc.)], coupling constant(s) and assignment. Diastereotopic protons are assigned as X and X', where the ' indicates the lower f ield proton. Carbon magnetic resonance spectra were recorded on Varian Mercury400 (100MHz) and Varian Unity/Inova500 (125MHz) spectrometers. Carbon spectra assignments are supported by DEPT editing and where necessary C-H (HMQC) correlations. Chemical shifts (δC) are quoted in ppm to the nearest 0.01ppm, and are referenced to tetramethylsilane (internal). Fluorine magnetic resonance spectra (F) were recorded on a Varian Mercury300 (282MHz) spectrometer. Chemical shifts (δF) are quoted in ppm to the nearest 0.01ppm and are referenced to CF3CH2OH (external). 4