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

Okamoto, Sentaro; He, Jing‐Qian; Ohno, Chihaya; Oh-iwa, Yuhji; Kawaguchi, Yuhki

doi:10.1016/j.tetlet.2009.11.027

Cited by 24 publications

(14 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The method was once widely exploited [16] but recent usage is scant [17]. Recent methods of production of 1,2-diols from carbonyl compounds rely on catalysis by metal complexes, notably of Ti [18,19,20,21]. The yields in Figure 1 show that 1,2-diol was formed by direct UVA photolysis, under our conditions, in the absence of catalyst.…”

Section: Resultsmentioning

confidence: 84%

Hydrogenations without Hydrogen: Titania Photocatalyzed Reductions of Maleimides and Aldehydes

et al. 2014

View full text Add to dashboard Cite

Abstract: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.

show abstract

Section: Resultsmentioning

confidence: 84%

Hydrogenations without Hydrogen: Titania Photocatalyzed Reductions of Maleimides and Aldehydes

et al. 2014

View full text Add to dashboard Cite

show abstract

“…[20] 4.2. McMurry Coupling and Imino-Pinacol Coupling [34] McMurry coupling olefination of carbonyl compounds is one of the most well-known reactions mediated by LVT reagents. For this transformation, many combinations of titanium sources, reductants, additives, and solvents have been developed.…”

Section: Bond-forming Reactionsmentioning

confidence: 99%

“…[34] Note that imines derived from aliphatic aldehydes were also converted to the corresponding 1,2-diamines in a dl-selective fashion, although the yields were not necessarily high.…”

Section: Bond-forming Reactionsmentioning

confidence: 99%

See 1 more Smart Citation

Synthetic Reactions Using Low-valent Titanium Reagents Derived from Ti(OR)₄or CpTiX₃(X = O-i-Pr or Cl) in the Presence of Me₃SiCl and Mg

Okamoto

2016

The Chemical Record

Self Cite

View full text Add to dashboard Cite

In the presence of Me3SiCl, Ti(OR)4 or CpTiX3 (X = O-i-Pr or Cl) is reduced by Mg powder in THF to gradually generate a specific low-valent titanium (LVT) species that mediates several synthetic reactions. The LVT-catalyzed C-O bond-cleaving reactions of allyl and propargyl ethers and esters generate parent alcohols and carboxylic acids, respectively. O-allyl and propargyl carbamates are also readily deprotected by the LVT to afford parent amines. In addition, the respective reductive N-S or O-S bond cleavage of sulfonamides or sulfonyl esters mediated by the LVT was developed as a novel facile deprotection method. The reagent catalyzes intra- and intermolecular alkyne or alkyne/nitrile cycloaddition to produce substituted benzenes and pyridines, while epoxides and oxetanes are reduced to alcohols via an LVT-mediated homolytic ring opening. The McMurry coupling of aryl aldehydes and ketones proceeds with the LVT under homogeneous and mild reaction conditions and is effective for the polymerization of aromatic dialdehydes, generating conjugated polymers. Finally, imino-pinacol coupling of imines is mediated by the LVT to provide 1,2-diamines.

show abstract

“…Given that they are highly reducing, Ti II reagents have typically been formed from the reaction of Ti IV halide precursors with powerful reductants: KC 8 , 2,7b LiAlH 4 ,11 Na/Hg, 15 and Mg. 16 Recently, we have reported several catalytic oxidative C–N bond forming reactions that proceed through a formal Ti II /Ti IV redox couple (Scheme 1). These reactions presumably generate a Ti II intermediate in the absence of a strong metal reductant by coupling a Ti IV imido unit with two alkynes (or an alkyne and an alkene).…”

Section: Introductionmentioning

confidence: 99%

Generation of Ti^II Alkyne Trimerization Catalysts in the Absence of Strong Metal Reductants

et al. 2017

View full text Add to dashboard Cite

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

show abstract

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

Cited by 24 publications

References 22 publications

Hydrogenations without Hydrogen: Titania Photocatalyzed Reductions of Maleimides and Aldehydes

Hydrogenations without Hydrogen: Titania Photocatalyzed Reductions of Maleimides and Aldehydes

Synthetic Reactions Using Low-valent Titanium Reagents Derived from Ti(OR)₄or CpTiX₃(X = O-i-Pr or Cl) in the Presence of Me₃SiCl and Mg

Generation of Ti^II Alkyne Trimerization Catalysts in the Absence of Strong Metal Reductants

Contact Info

Product

Resources

About

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

Cited by 24 publications

References 22 publications

Hydrogenations without Hydrogen: Titania Photocatalyzed Reductions of Maleimides and Aldehydes

Hydrogenations without Hydrogen: Titania Photocatalyzed Reductions of Maleimides and Aldehydes

Synthetic Reactions Using Low-valent Titanium Reagents Derived from Ti(OR)4or CpTiX3(X = O-i-Pr or Cl) in the Presence of Me3SiCl and Mg

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

Contact Info

Product

Resources

About

Synthetic Reactions Using Low-valent Titanium Reagents Derived from Ti(OR)₄or CpTiX₃(X = O-i-Pr or Cl) in the Presence of Me₃SiCl and Mg

Generation of Ti^II Alkyne Trimerization Catalysts in the Absence of Strong Metal Reductants