Catalytic C-Alkylation of Pyrroles with Primary Alcohols: Hans Fischer's Alkali and a New Method with Iridium P,N,P-Pincer Complexes
作者:Sebastian Koller、Max Blazejak、Lukas Hintermann
DOI:10.1002/ejoc.201800146
日期:2018.4.17
The alkylation of pyrroles with primary alcohols and alkali base at 220 °C was realized by Hans Fischer one hundred years ago. However, this hydrogen‐autotransfer (borrowing‐hydrogen) alkylation proceeds under much milderconditions in the presence of iridium P,N,P‐pincer complex catalysts.
Biosynthesis of Benzylic Derivatives in the Fermentation Broth of the Edible Mushroom, <i>Ischnoderma resinosum</i>
作者:Purni C. K. Wickramasinghe、John P. Munafo
DOI:10.1021/acs.jafc.9b07218
日期:2020.2.26
a series of benzylic derivatives was elucidated in the fermentation broth of the edible mushroom Ischnoderma resinosum (P. Karst). Twenty-six hydroxy- and methoxy- benzylic derivatives were screened by gas chromatography-mass spectrometry (GC-MS) of which 13 were detected in the culture media. Results from the isotope incubation studies showed the transformation of both benzyl alcohol and benzoic acid
Skeletal rearrangements on chemical ionization of dibenzyl ether and derivatives
作者:Eric E. Kingston、James S. Shannon、Vladimir Diakiw、Michael J. Lacey
DOI:10.1002/oms.1210161003
日期:1981.10
AbstractProtonated molecular ions of dibenzyl ether, formed by chemical ionization using hydrogen and isobutane as reagent gases, undergo skeletal rearrangements to lose water and formaldehyde, both in the ion source and the flight path. The rearrangements have been elucidated by deuterium labelling and chemical substitution. The water lost contains the reagent proton and an aromatic hydrogen atom, and the aromatic hydrogen atoms have been shown to be mobile prior to the reaction. It is proposed that the skeletal rearrangement for water loss is initiated by protonation on the ether oxygen atom, followed by benzyl migration. The formaldehyde lost contains benzylic hydrogen atoms exclusively, and it is proposed that the skeletal rearrangement is preceded by hydrogen rearrangement of an oxygen protonated molecular ion to a ring protonated molecular ion. Daughter ion structures are supported by comparisons of their collision induced dissociation spectra with those of isomeric ions prepared by alternative routes.