McMurry coupling of aryl aldehydes and imino pinacol coupling mediated by Ti(O-i-Pr)4/Me3SiCl/Mg reagent

Simple electrochemical reduction of nitrones to amines

The use of electricity allows the reduction of nitrones containing aromatic and heteroaromatic rings to the corresponding amines. The main advantage of this protocol relies on the fact that only electrons are needed, avoiding the use of different chemicals and harsh procedures, something that reinforces some green aspects. The conversion tolerates different moieties and a large variety of functional groups. In addition, this electrolysis can be performed on a simple undivided beaker-type cell with constant current conditions.

Generation of TiII Alkyne Trimerization Catalysts in the Absence of Strong Metal Reductants

Low-valent Ti^II species have typically been synthesized by the reaction of Ti^IV halides with strong metal reductants. Herein we report that Ti^II species can be generated simply by reacting Ti^IV imido complexes with 2 equiv of alkyne, yielding a metallacycle that can reductively eliminate pyrrole while liberating Ti^II. In order to probe the generality of this process, Ti^II-catalyzed alkyne trimerization reactions were carried out with a diverse range of Ti^IV precatalysts.

Hydrogenations without hydrogen: titania photocatalyzed reductions of maleimides and aldehydes

A mild procedure for the reduction of electron-deficient alkenes and carbonyl compounds is described. UVA irradiations of substituted maleimides with dispersions of titania (Aeroxide P25) in methanol/acetonitrile (1:9) solvent under dry anoxic conditions led to hydrogenation and production of the corresponding succinimides. Aromatic and heteroaromatic aldehydes were reduced to primary alcohols in similar titania photocatalyzed reactions. A mechanism is proposed which involves two proton-coupled electron transfers to the substrates at the titania surface.

Non-Cp titanium alkoxide-based homolytic ring-opening of epoxides by an intramolecular hydrogen abstraction in β-titanoxy radical intermediates

A low-valent titanium species derived in situ from Ti(O-i-Pr)(4), Me(3)SiCl and Mg powder in tetrahydrofuran reacted with epoxides to selectively provide less hindered alcohols via a homolytic ring-opening of epoxides, in which the intermediate β-titanoxy radical intramolecularly abstracted a hydrogen atom from an alkoxy moiety in the titanium complexes.