36306-47-5Relevant articles and documents
Radical condensation between benzylic alcohols and acetamides to form 3-arylpropanamides
Azizi, Kobra,Madsen, Robert
, p. 7800 - 7806 (2020/08/14)
A new radical condensation reaction is developed where benzylic alcohols and acetamides are coupled to generate 3-arylpropanamides with water as the only byproduct. The transformation is performed with potassium tert-butoxide as the only additive and gives rise to a variety of 3-arylpropanamides in good yields. The mechanism has been investigated experimentally with labelled substrates, trapping experiments and spectroscopic measurements. The findings indicate a radical pathway where potassium tert-butoxide is believed to serve a dual role as both base and radical initiator. The radical anion of the benzylic alcohol is proposed as the key intermediate, which undergoes coupling with the enolate of the amide to form the new C-C bond. Subsequent elimination to the corresponding cinnamamide and olefin reduction then affords the 3-arylpropanamides.
Reductive Lithiation in the Absence of Aromatic Electron Carriers. A Steric Effect Manifested on the Surface of Lithium Metal Leads to a Difference in Relative Reactivity Depending on Whether the Aromatic Electron Carrier Is Present or Absent
Kennedy, Nicole,Lu, Gang,Liu, Peng,Cohen, Theodore
, p. 8571 - 8582 (2015/09/15)
One of the most widely used methods of preparation of organolithium compounds is by the reductive lithiation of alkyl phenyl thioethers or, usually less conveniently, alkyl halides with either aromatic radical-anions of lithium or lithium metal in the presence of an aromatic electron-transfer catalyst. Here we present results showing that lithium dispersion can achieve reductive lithiation in the absence of the electron-transfer agent. This procedure is more efficient, and surprisingly, the order of reactivity of substrates is reversed depending on whether the electron-transfer agent is present or absent. For example, in the presence of a preformed radical-anion, tert-butyl phenyl sulfide cleaves significantly faster than methyl phenyl sulfide, whereas in the absence of the radical-anion, it is just the opposite. Density functional theory calculations reveal that the exothermicity of the cleavage of the C-S bond in alkyl phenyl thioethers on the lithium surface is dependent on the size of the alkyl group, the smaller the alkyl group the greater the exothermicity. The increased reactivity is attributed to the smaller steric repulsion between the alkyl group and the lithium surface. The methodology includes, but may not be limited to, the lithium dispersion reductive lithiation of phenyl thioethers, alkyl chlorides, acrolein diethyl acetal, and isochroman.
Cp*Ru(PN) complex-catalyzed isomerization of allylic alcohols and its application to the asymmetric synthesis of muscone
Ito, Masato,Kitahara, Sachiko,Ikariya, Takao
, p. 6172 - 6173 (2007/10/03)
Highly efficient isomerization of allylic alcohols into saturated carbonyls is accomplished using the catalyst system of Cp*RuCl[Ph2P(CH2)2NH2-κ2-P,N]-KOt-Bu (Cp* = η5-C5(CH3)5) under mild conditions. Mechanistic consideration based on isotope-labeling experiments indicated the present reaction is applicable to the asymmetric isomerization of racemic sec-allylic alcohols with a prochiral olefin via dynamic kinetic resolution. A concise asymmetric synthesis of muscone has been achieved, where the asymmetric isomerization using an optically active ligand is a key reaction. Copyright
Highly diastereoselective hydrostannylation of allyl and homoallyl alcohols with dibutyl(trifluoromethanesulfoxy)stannane
Miura, Katsukiyo,Wang, Di,Hosomi, Akira
, p. 9366 - 9367 (2007/10/03)
Dibutyl(trifluoromethanesulfoxy)stannane (Bu2Sn(OTf)H, 1a) was found to be very valuable for highly diastereoselective homolytic hydrostannylation of allyl and homoallyl alcohols. α,β-Disubstituted allyl alcohols and α,γ-disubstituted homoallyl alcohols were converted into γ- and δ-stannylated alcohols with high 1,2-syn and 1,3-syn diastereoselectivity, respectively. The origin of the stereochemical outcomes can be rationalized by conformational fixation of the intermediary β-stannylalkyl radical by coordination of the hydroxy group to the Lewis acidic tin center. Copyright
STUDIES OF THE STABILITY AND RECTIVITY OF SUBSTITUTED VINYL TITANIUM TRIISOPROPOXIDES
Boeckman, Robert K. Jr.,O'Connor, Kenneth J.
, p. 3271 - 3274 (2007/10/02)
The stability and reactivity of vinyl titanium triisopropoxides having a variety of substitution patterns has been explored.These reagents when prepared in Et2O have proven to be more stable than expected based on prior reports, and they exhibit sufficien
STEREOSELECTIVITY IN THE HYDROBORATION OF CHIRAL CYCLOHEXANE-DERIVED ALLYLIC ALCOHOLS
Birtwistle, David H.,Brown, John M.,Foxton, Michael W.
, p. 4367 - 4370 (2007/10/02)
The isomeric 2-ethylidenecyclohexanols are hydroborated by t-hexylborane with weak stereoselectivity whilest 1-(1'-hydroxyalkyl)cyclohexenes show up to 50:1 discrimination.
SELECTIVE GRIGNARD-TYPE CARBONYL ADDITION OF ALKENYL HALIDES MEDIATED BY CHROMIUM(II) CHLORIDE
Takai, Kazuhiko,Kimura, Keizo,Kuroda, Tooru,Hiyama, Tamejiro,Nozaki, Hitosi
, p. 5281 - 5284 (2007/10/02)
Alkenyl (or aryl) iodide (or bromide) is readily reduced with CrCl2 in N,N-dimethylformamide at 25oC to give the corresponding organochromium species which adds selectively to an aldehyde moiety without affecting the coexisting ketone or cyano group of the substrate.
Alkyl-, Aryl-, Vinyl-, and Heterosubstituted Organozirconium Compounds. -Selective Nucleophiles of Low Basicity
Weidmann, Beat,Maycock, Christopher D.,Seebach, Dieter
, p. 1552 - 1557 (2007/10/02)
Solutions of the title compounds are accessible from organolithium reagents and trialkoxyzirconium chloride (equation 2).In contrast to their titanium analogues, vinylzirconium reagents are stable enough to be employed.Generally, organozirconium reagents are highly selective aldehyde and ketone carbonylophiles of exceedingly low basicity (Tables 1, 2, 3 and typical procedure).
