I.R. laser chemistry of allyl phenyl ether

Abstract

The Claisen rearrangement of allyl phenyl ether to 2-allyl phenol has been investigated by I.R. multiphoton excitation. While the thermal reaction of the same starting material yields only the Claisen isomerization product, the I.R. photochemical excitation initiates both fragmentation and isomerization reactions. The dependence of product distribution on fluence is different at various wavelengths. Two mechanisms are proposed for the I.R. photochemical reaction. One assumes selective absorption, the other assumes wavelength dependent competition between absorption and stimulated emission of the vibrationally excited reaction intermediates.

Spiropyrans and Spirooxazines for Memories and Switches

“…Nevertheless, such wavelength-selective IR laser induced chemical reactions were observed in the gas phase. 93 Finally, the results of Figure 6 also reveal that the exposure sensitivities are essentially independent of spiropyran concentrations; this indicates that the intermolecular merocyanine interactions and/or the degree of aggregate formation do not play a significant role within the concentration range that we considered.…”

“…It must be noted that, with organic solids, it is extremely difficult to measure differences in vibrational excitation and relaxation processes, because the intermolecular energy dissipation is normally dominant. Nevertheless, such wavelength-selective IR laser induced chemical reactions were observed in the gas phase . Finally, the results of Figure also reveal that the exposure sensitivities are essentially independent of spiropyran concentrations; this indicates that the intermolecular merocyanine interactions and/or the degree of aggregate formation do not play a significant role within the concentration range that we considered.…”

Bond-Breaking/Bond-Forming Reactions by Vibrational Excitation: Infrared-Induced Bidirectional Tautomerization of Matrix-Isolated Thiotropolone

“…This is partially because intramolecular vibrational energy redistribution (IVR) dissipates the deposited energy fast to other modes before the reaction arises. , Alternatively, if a dominant (nonstatistical) IVR pathway exists due to the coupling between an excited vibrational mode and a reaction coordinate, this might be exploited to induce a desired chemical transformation in an elegant and selective way. , One remarkable example illustrating this possibility is the vibrationally induced unimolecular reaction of the jet-cooled Criegee intermediate syn -CH 3 CHOO, reported by Lester and co-workers − The authors demonstrated that excitation of CH stretching overtones or combination modes induces a 1,4-H shift from the methyl group to the terminal oxygen and activates decomposition of the molecule (Scheme ). Nevertheless, the application of this strategy to induce and control organic reactions remains scarcely explored. − …”

Catalytic Ethanolysis of Enzymatic Hydrolysis Lignin over an Unsupported Nickel Catalyst: The Effect of Reaction Conditions

“…As reported, the phenolic compounds containing alkenyl side chains undergo alkenyl elimination steps to remove their side chains in thermal reaction. 44,45 Therefore, the Ph may originate from the elimination of alkenyl side chains of intermediates. At 280 °C under 0 MPa H 2 , the alkenyl elimination reaction was favorable because the hydrogenation of alkenyl side chains into alkyl side chains not readily occur, thus promoting the formation of Ph.…”

“…The elimination of side chains seems not through the cleavage of C-C linkages on the Ni (220H) catalyst, as the 2D-HSQC NMR analysis results demonstrated that the cleavage of C-C linkages was suppressed under 0 MPa H2. As reported, the phenolic compounds containing alkenyl side chains undergo alkenyl elimination step to remove their side chains in thermal reaction44,45 . Therefore, the Ph may originate from the elimination of alkenyl side chains of intermediates.…”