50599-44-5

Upstream product

• 2550-26-7 4-Phenyl-2-butanone 
• 122-57-6 1-Phenylbut-1-en-3-one 

Downstream Products

• 139373-55-0 4,4-dimethyl-1,6-diphenylhexan-3-one 
• 139373-54-9 3-methyl-3-phenethyl-5-phenyl-2-pentanone 

Relevant academic research and scientific papers

Ketyl-type radicals from cyclic and acyclic esters are stabilized by SmI2(H2O)n: the role of SmI2(H 2O)n in post-electron transfer steps

Mechanistic details pertaining to the SmI2-H2O- mediated reduction and reductive coupling of 6-membered lactones, the first class of simple unactivated carboxylic acid derivatives that had long been thought to lie outside the reducing range of SmI2, have been elucidated. Our results provide new experimental evidence that water enables the productive electron transfer from Sm(II) by stabilization of the radical anion intermediate rather than by solely promoting the first electron transfer as originally proposed. Notably, these studies suggest that all reactions involving the generation of ketyl-type radicals with SmI2 occur under a unified mechanism based on the thermodynamic control of the second electron transfer step, thus providing a blueprint for the development of a broad range of novel chemoselective transformations via open-shell electron pathways.

Reductive coupling of carbonyl compounds promoted by cobalt or titanium nanoparticles

The reaction of a series of aldehydes and ketones with readily prepared cobalt or titanium nanoparticles, under mild reaction conditions, led to the obtention of different reductive dimerization products depending on the nature of the transition metal used. Cobalt nanoparticles (CoNPs) allowed the selective transformation of the starting carbonyl compounds into vicinal diols, whereas the reaction promoted by titanium nanoparticles (TiNPs) led to the formation of the corresponding alkenes. In this last case, the use of trimethylsilyl chloride (TMSCl) as additive, at 0 °C, also allowed the obtention of vicinal diols after acidic aqueous work-up. ARKAT-USA, Inc.

Exploring SmBr2-, SmI2-, and YbI2-mediated reactions assisted by microwave irradiation

The use of microwave heating in lanthanide(II) halide (LnX2 = SmBr2, SmI2, and YbI2) mediated reduction and coupling reactions has been investigated for a variety of functional groups including α,β-unsaturated esters, aldehydes, ketones, imines, and alkyl halides. Good to quantitative transformations were obtained within a few minutes without the addition of any co-solvents, such as hexamethyl phosphoramide (HMPA). The redox potential of YbI2 in tetrahydrofuran (THF) has been determined as -1.02± 0.05 V (versus Ag/AgNO3) by cyclic voltammetry. A large selectivity difference in various reactions was observed depending on the redox potential of the LnX2 reagent. The more powerful reductant, SmBr2, afforded mainly pinacol-coupling products of ketones whereas the weaker reductant YbI2 afforded mainly reduction products. The results indicate that the reducing power of LnX 2 has a large impact on not only the pinacol coupling/reduction product ratio of ketones but also on other substrates in which there are competing coupling and reduction reactions. The use of in situ generated LnX2 has also been explored and proven useful in many of these reactions.

Novel and efficient Ni-mediated pinacol coupling of carbonyl compounds

It was firstly found that the Rieke Ni generated in situ was able to promote the pinacol coupling of various carbonyls efficiently. Based on this information, another catalytically effective, cheaper and more convenient NiCl2(Cat.)/Mg/TMSCl system was designed and developed further successfully. The interesting single-electron transfer (SET) mechanisms for the coupling reactions were proposed. Additionally, the DL/meso diastereoselectivity and some additive effects were also explained in terms of the proposed mechanisms.

A highly diastereoselective pinacol coupling reaction of aldehydes and ketones using low-valence niobium generated from Nb(V)

A simple method for the diastereoselective synthesis of racemic 1,2-diol mediated by low-valence niobium generated in situ is described. A 1,4-dioxane-toluene solvent system was found to be essential to achieve higher selectivities and to prevent other reactions of pinacols, such as deoxygenation and acetal formation. Aromatic aldehydes and ketones were converted to the corresponding pinacols with up to 97 and 85% de, respectively.

A new preparation of samarium dibromide and its use in stoichiometric and catalytic pinacol coupling reactions

A new convenient preparation of samarium dibromide in THF is reported. Pinacol coupling reactions using SmBr2 in catalytic amounts together with mischmetall as a coreductant have been performed with a variety of carbonyl compounds.

Isolation, X-ray structural characterization, and reactivities of diiodosamarium(II) complexes bearing amide compounds as ligands

The structures of diiodosamarium(II) complexes with amide compounds have been investigated basing on single crystal X-ray structural analyses. The reaction of [SmI2(thf)2] with 2 equivalents of tetramethylurea (TMU) gave [SmI2(thf)2(tmu)2] (1). The three different kinds of ligands in 1 attach to the samarium atom in a trans orientation. [SmI2(thf)2] reacted with 4 equivalents of 1,3-dimethyl-2-imidazolidione (DMI) to afford [SmI2(dmi)4] (2), forming a typical hexa-coordinated octahedral structure. Diiodosamarium complex containing four N,N-dimethylacetamide (DMA) ligands [SmI2(dma)4] (3) was prepared by treatment of [SmI2(thf)2] with 4 equivalents of DMA. The reaction of [SmI2(thf)2] with 6 equivalents of 1,3-dimethyl-3,4,5,6-tetrahydro-2-(1H)-pyrimidinone (dimethylpropyleneurea (DMPU)) gave [Sm(dmpu)6]I2 (4) quantitatively. This complex experiences a unique coordination fashion, in which six DMPU ligands coordinate to the samarium atom to overlap each other. [SmI2(dmpu)3(thf)] (5) was isolated from the reaction of [SmI2(thf)2] with 2 equivalents of DMPU. The reducing ability of these complexes was evaluated by reactions with benzylacetone or 9-haloanthracene. The structural analyses and reactivity studies of these complexes indicate that DMPU and DMA ligands are the most effective among the amide compounds to enhance the reducing ability of samarium diiodide.

Efficient method for the preparation of pinacols derived from aromatic and aliphatic ketones by using low-valent titanium reagents in dichloromethane-pivalonitrile

The reductive coupling reaction of aldehydes and ketones, including unsymmetrical aliphatic ketones, proceeded smoothly to give the corresponding pinacols in good to high yields under mild conditions by using combination of titanium(II) chloride and zinc or titanium(IV) chloride and zinc in dichloromethane-pivalonitrile. Meso-selective formation of the coupling products was observed in the cases of some aliphatic ketones. The diastereoselectivities of coupling products depend on both difference of bulkiness of 2-, and 2'-substituents of carbonyl group of the reactant, and overall steric effect around the carbonyl groups.

Efficient method for pinacol coupling of aromatic and aliphatic ketones by using titanium(II) chloride and zinc in the presence of pivalonitrile

The reductive coupling reaction of aromatic and aliphatic ketones including acyclic aliphatic ketones proceeded smoothly to give the corresponding pinacols in good to high yields below room temperature by the combined use of titanium(II) chloride and zinc in the presence of pivalonitrile. Meso-selective formation of the coupling products was observed in the cases with some acyclic aliphatic ketones.

Trimethylsilyl chloride-accelerated reduction and pinacol coupling of carbonyl compounds by means of samarium diiodide

The combination of samarium diiodide (SmI2) and trimethylsilyl chloride (Me3SiCl) in THF-HMPA is found to accelerate the reduction of sterically hindered and enolisable ketones, and also to accelerate pinacolisation of the carbonyl compounds depending on the reaction conditions.