22188-02-9Relevant articles and documents
Trans-Selective and Switchable Arene Hydrogenation of Phenol Derivatives
Bergander, Klaus,Glorius, Frank,Heusler, Arne,Wollenburg, Marco
, p. 11365 - 11370 (2020)
A trans-selective arene hydrogenation of abundant phenol derivatives catalyzed by a commercially available heterogeneous palladium catalyst is reported. The described method tolerates a variety of functional groups and provides access to a broad scope of trans-configurated cyclohexanols as potential building blocks for life sciences and beyond in a one-step procedure. The transformation is strategically important because arene hydrogenation preferentially delivers the opposite cis-isomers. The diastereoselectivity of the phenol hydrogenation can be switched to the cis-isomers by employing rhodium-based catalysts. Moreover, a protocol for the chemoselective hydrogenation of phenols to cyclohexanones was developed.
The mechanism of methanol loss from the (M-H) ions of cis- And trans-4-methoxycyclohexanol. the application of experiment and theory in concert
Dua, Suresh,Buntine, Mark A.,Raftery, Mark J.,Eichinger, Peter C. H.,Bowie, John H.
, p. 2489 - 2496 (2007/10/03)
Deprotonation of cis- and trans-4-methoxycyclohexanol by HO- in the ion source of a mass spectrometer yields the (M - H)- alkoxide ions exclusively. Both of these ions, on collisional activation, form MeO-, MeO-(H2O) and eliminate MeOH. The loss of methanol forms the base peak of the spectrum, and the structure of this daughter anion is shown to be the alkoxide ion from cyclohex-3-enol for both isomers. Evidence (based on product ion, deuterium labelling and AMI semiempirical computational studies) indicates that the loss of methanol from the trans isomer proceeds by an internal SN2 cyclisation of O- at the four position (through a 1,4-epoxycyclohexane species) followed by 3,4 elimination. A similar sequence may occur for the cis-isomer, but in this case the process is not as energetically favourable as that for the trans isomer.
