Cover Picture: Ruthenium-Catalyzed Propargylic Substitution Reactions of Propargylic Alcohols with Oxygen-, Nitrogen-, and Phosphorus-Centered Nucleophiles (Chem. Eur. J. 5/2005)

Ruthenium-catalyzed enantioselective propargylation of aromatic compounds with propargylic alcohols via allenylidene intermediates.

Highly enantioselective copper-catalyzed propargylic substitution of propargylic acetates with 1,3-dicarbonyl compounds.

A chiral tridentate ketimine P,N,N-ligand has been successfully applied in the copper-catalyzed enantioselective propargylic substitution of propargylic acetates with a variety of β-dicarbonyl compounds, in which excellent enantioselectivities (up to >99% ee) and high yields have been obtained.

Regioselective Dihalohydration Reactions of Propargylic Alcohols: Gold-Catalyzed and Noncatalyzed Reactions**

The regioselective conversion of propargylic alcohols into previously unreported α,α-diiodo-β-hydroxyketones was achieved by treatment with N-iodosuccinimide in the presence of a gold catalyst. The corresponding α,α-dichloro-β-hydroxyketones were obtained by treatment with trichloroisocyanuric acid in the absence of a catalyst. The latter reaction can be extended to other alkynols. These transf...

Directed hydrozirconation of propargylic alcohols.

Hydrozirconation of alkynes with Cp2ZrH(Cl) (Schwartz reagent) generates vinyl zirconium species reliably, stereospecifically, and regioselectively. These organometallic reagents can participate in cross-coupling reactions, conjugate and nucleophilic additions, and can undergo carbonylation and halogenation.1 Hydrozirconation of terminal alkynes often proceeds with >50:1 selectivity to form the...

Iron-catalyzed carbometalation of propargylic and homopropargylic alcohols.

Nucleophilic addition to alkynes represents an attractive approach to the synthesis of olefins. Obstacles to this strategy include the low reactivity of alkynes toward many organometallic reagents and difficulties associated with controlling the regioselectivity of addition. Here we demonstrate that Fe(III) salts are effective precatalysts for the carbometalation of alkynes. Primary and seconda...