The Intricate Assembling ofgem-Diphenylpropargylic Units

Propargylation of CoQ0 through the Redox Chain Reaction

An efficient catalytic propargylation of CoQ0 is described by employing the cooperative effect of Sc(OTf)₃ and Hantzsch ester. It is suggested to work through the redox chain reaction, which involves hydroquinone and dimeric propargylic moiety intermediates. A broad range of propargylic alcohols can be converted into the appropriate derivatives of CoQ0 containing triple bonds in good to excellent yields. The mechanism of the given transformation is also discussed.

1-Methoxy-1,1-diphenylbut-2-yne

In the title compound, C17H16O, the phenyl rings are twisted relative to each other at an angle of 85.9 (1)°. The crystal structure features weak C—H...π interactions, which connect the molecules into a three-dimensional supramolecular network.

3,4-Dibromo-2,2,5,5-tetraphenyl-2,5-dihydrofuran

The crystal structure of the title compound, C28H20Br2O, was solved in the orthorhombic space group P212121 with one molecule in the asymmetric unit. The phenyl rings are nearly planar and inclined at angles of 67.7 (1), 68.8 (1), 79.3 (1) and 62.3 (1)° to the plane of the 2,5-dihydrofuran ring. The crystal structure features C—H...π and Br...Br interactions, which connect the molecules to a three-dimensional supramolecular network.

On terminal alkynylcarbinols and derivatization thereof

The chemistry of three prototypes of secondary alkynylcarbinols (ACs), recently highlighted as challenging targets in anti-tumoral medicinal chemistry, is further documented by results on n-alkyl, alkynyl and alkenyl representatives. The N-naphthyl carbamate of an n-butyl-AC is thus characterized by X-ray crystallography. A novel dialkynylcarbinol (DAC) with synthetic potential is described, namely the highly dissymmetrical triisopropylsilyl-protected version of diethynylmethanol. The latter is shown to act as a dipolarophile in a selective Huisgen reaction with benzyl azide under CuAAC click conditions, giving an alkenyl-AC, where the alkene unsaturation is embedded in a 1,4-disubstituted 1,2,3-triazole ring, as confirmed by X-ray crystallography.

Identification of chiral alkenyl- and alkynylcarbinols as pharmacophores for potent cytotoxicity

Illumination by acetylene: Systematic structural variations in a series of archetypal acetylenic lipids derived from the naturally occurring (S,E)-icos-4-en-1-yn-3-ol allowed the discovery of a series of 3R-like 1,4-di-unsaturated carbinol units with a significant and systematic enantiomeric effect on cytotoxicity.

The chemistry of bisallenes

This review describes the preparation, structural properties and the use of bisallenes in organic synthesis for the first time. All classes of compounds containing at least two allene moieties are considered, starting from simple conjugated bisallenes and ending with allenes in which the two cumulenic units are connected by complex polycyclic ring systems, heteroatoms and/or heteroatom-containing tethers. Preparatively the bisallenes are especially useful in isomerization and cycloaddition reactions of all kinds leading to the respective target molecules with high atom economy and often in high yield. Bisallenes are hence substrates for generating molecular complexity in a small number of steps (high step economy).

Gold-catalyzed propargylic substitutions: Scope and synthetic developments

This personal account summarizes our recent developments in gold-catalyzed direct substitutions on propargylic (allylic, benzylic) alcohols, with various nucleophiles (and bi-nucleophiles) based on the σ- and/or π-acidity of gold(III) complexes. Synthetic developments are also briefly described.