A Facile Reaction of Unactivated Imines with Telluronium Allylide . Highly Stereoselective Synthesis of Vinylaziridines
Supporting Information General methods. Infrared spectra were recorded on a Nicolet AVATAR-360 spectrometer. H NMR and C NMR spectra were recorded at Bruker AM-300 instruments. Low resolution mass spectra (m/z) were recorded on HP5989A. High-resolution mass spectra were recorded on Concept 1H or MALDI/DHB. Microanalyses were performed using a Elemantar Vario EL. All reaction flasks were dried by flame. And all reactions were carried out under argon unless otherwise noted. THF and toluene were dried by distilled over sodium-benzophenone ketyl prior to use. N-aryl imines and -amidoalkyl-p-tolyl sulfones were prepared according to literature methods.
The Wittig Rearrangement
In 1942 Wittig and Lohmann described the isomerization of α-lithiated ethers (2; R = Me or CH2Ph) to skeletally rearranged lithio alkoxides (3; equation 1).1 Subsequent work by Wittig and others established that a variety of ethers undergo the Wittig rearrangement, provided the α-anion is stabilized by an aryl substituent. Of the several mechanisms proposed for this reaction a sequence involving homolysis of the anion intermediate (5), followed by recombination of the radical and radical anion fragments (equation 2) best accommodates the experimental findings.1–4
Identification of Dihydroxy Aromatic Compounds in a Low-Temperature Pyrolysis Coal Tar by Gas Chromatography−Mass Spectrometry (GC−MS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS)
Dihydroxy aromatics in coal tar undergo rapid coupling reactions with each other and with some coal-derived species during coal pyrolysis and liquefaction. However, only limited information on the structure of dihydroxy aromatics is known. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography−mass spectrometry (GC−MS) were used to characterize the dihydroxy aromatics in a low-temperature pyrolyzed coal tar and its distillate and residue fractions. Negative-ion electrospray ionization (ESI) FT-ICR MS spectra of coal-tar-derived samples had low molecular masses and narrow mass ranges. Negative-ion ESI is extremely selective for the dihydroxy aromatics present in coal tar. The O2 class species had the highest ion intensity among the species in the negative-ion FT-ICR mass spectrum for each sample. Dihydroxy compounds with an aromatic core structure of benzene, indan, biphenyl (and/or acenaphthene), and naphthalene were identified in the distillate fract...