[reaction: see text]. 1,2,3,5-tetrasubstituted pyrroles can be synthesized in good yields in a one-pot, three-step, four-component process by a coupling-isomerization-Stetter reaction-Paal-Knorr sequence of an electron-poor (hetero)aryl halide, a terminal propargyl alcohol, an aldehyde, and a primary amine. The structures of the 1,4-diketone 4f and the pyrrole 6b were additionally supported by X-ray structure analyses.

Infrared (IR) laser-induced resonant desorption/ablation of benzene layers condensed on liquid-nitrogen-cooled substrates has been investigated using the time-of-flight (TOF) technique. Adsorbates of up to 5 μm thickness were irradiated with a line-tuned TEA CO2 laser. Time-resolved detection of desorbed particles was performed with a quadrupole mass spectrometer (QMS). Measured TOF spectra can usually be well fitted with a stream-modified Maxwell–Boltzmann distribution. Systematic deviations from these fits were observed depending on film thickness, laser fluence, and angle of detection. Spectroscopic data of the adsorbate–substrate system needed for model calculations were measured in situ. The absorption coefficients were found to be fluence dependent. Measurements of the desorption yield and kinetic energy of the desorbed particles were performed with the P932 and P934-CO2 laser lines as a function of film thickness and laser fluence. The solid–liquid phase transition could clearly be observed in these experiments. Average kinetic energies of up to 0.8 eV were measured in the TOF spectra, where the adsorbate temperature could be estimated to be less than 600 K. IR multilayer laser-induced desorption (LID) exhibits features very similar to those reported for UV multilayer LID. A mechanism based on the sudden rise of the adsorbate vapor pressure due to fast energy deposition by the laser pulse is discussed.

[reaction: see text] 2,4,6-Tri(hetero)aryl-substituted pyrimidines can be readily synthesized in a three-component one-pot process based upon a coupling-isomerization sequence of an electron-poor (hetero)aryl halide and a terminal propargyl alcohol subsequently followed by a cyclocondensation with amidinium salts.

Dynamic kinetic asymmetric transformation (DYKAT) of a series of 1,5-diols has been performed in the presence of Candida antarctica lipase B (CALB), Pseudomonas cepacia lipase II (PS-C II), and ruthenium catalyst 4. The resulting optically pure 1,5-diacetates are useful synthetic intermediates, which was demonstrated by the syntheses of both an enantiopure 2,6-disubstituted piperidine and an enantiopure 3,5-disubstituted morpholine.

The Sonogashira coupling of electron-deficient (hetero)aryl halides 1 and (hetero)aryl or alkenyl 1-propargyl alcohols 2 does not terminate at the stage of the expected internal propargyl alcohols, but rather gives rise to the formation of alpha,beta-unsaturated ketones 3 with a variety of acceptor substituents. This new domino reaction, a coupling-isomerization reaction (CIR), can be rationalized as a sequence of rapid Pd/Cu-catalyzed alkynylation followed by a slow amine-base-catalyzed propargyl alcohol-enone isomerization. Performing the CIR in deuterated protic solvents or with a selectively deuterated propargyl alcohol revealed that the base-catalyzed isomerization step proceeds through a formal 1,3-H shift with minimal H/D exchange with the surrounding solvent. Additionally, 19F NMR kinetic measurements on the isomerization step with the fluorinated propargyl alcohol 4 r support the mechanistic rationale.