A diastereoselective synthesis of cis-2,6-disubstituted tetrahydropyran-4-ones was developed. The key step of this methodology, a silyl enol ether Prins cyclization, was promoted by a condensation reaction between a hydroxy silyl enol ether and an aldehyde to afford substituted tetrahydropyran-4-ones. The cyclization was tolerant of many functional groups, and the modular synthesis of the hydro...

Stereodefined enol derivatives of aldehydes are prepared from terminal alkynes. Specifically, terminal alkynes are known to undergo Cp2ZrCl2-catalyzed methylalumination. Here, we show that the resultant vinylalanes can be oxygenated with peroxyzinc species to generate trisubstituted enolates. Electrophilic trapping with carboxylic anydrides or silyl triflates yields trisubstituted enol esters o...

We report the highly efficient gold-catalyzed hydrocarboxylation of internal alkynes that operates under solvent- and silver-free conditions. This new, simple, and eco-friendly protocol allows for the synthesis of a wide variety of functionalized aryl and alkyl enol esters in high yields, with Z-stereospecificity and good regioselectivities and without the requirement for purification by chroma...

The title Schiff base compound, 0.57C(17)H(12)FNO·0.43C(17)H(12)FNO, reveals both the enol (OH) and keto (NH) tautomeric forms with occupancies of 0.57 (6) and 0.43 (6), respectively. The tautomeric forms are stabilized by intra-molecular O-H⋯N (enol) and N-H⋯O (keto) hydrogen bonds. The dihedral angle between the naphthalene ring system and the benzene ring is 32.76 (1)°.

A variety of functionalized 3,4-benzo-7-hydroxy-2,9-diazabicyclo[3.3.1]non-7-enes were prepared by one-pot cyclizations of 1,3-bis(silyl enol ethers) with quinazolines. The mechanism of the cyclization was studied by B3LYP/6-31G(d) density functional theory computations. The products could be functionalized by Suzuki cross-coupling reactions. The reaction of 1,3-bis(silyl enol ethers) with phth...

The use of enol phosphinates as electrophiles for cross-coupling reactions has been explored. Both boronic acids (Suzuki-Miyaura reaction) and stannanes (Stille reaction) couple efficiently with lactam derived phosphinates.

A series of new tautomeric azonaphthols are synthesized and the possibilities for molecular switching are investigated using molecular spectroscopy, X-ray analysis and density functional theory quantum chemical calculations. Two opposite effects that influence switching are studied: attaching a piperidine sidearm, and adding substituents to the phenyl ring. On the one hand, the attached piperid...

We present R2PI, IR–UV and UV–UV double resonance measurements of the guanine–cytosine (G–C) dimer formed in a supersonic jet. We show that there is only one isomer of G–C in the investigated wavelength range from 33200 to 34100 cm . We assigned the observed G–C isomer to a specific structure, based on comparisons of the IR spectra of the G and C monomers with the G–C dimer in the range of the ...

The cathodic reduction of ω-bromomethylarylketones in aprotic organic solvents (such as propylene carbonate) containing tetraalkylammonium iodides achieved at smooth glassy carbon (GC) permits through a selective one-electron reduction, the scission of the C-Br bond. Quite unexpectedly, the free radical thus formed is prior attached to the carbon surface in its enolic form (GC-O-(Ar)C=CH2). Suc...