140695-01-8Relevant academic research and scientific papers
Gold(I)-catalysed direct thioetherifications using allylic alcohols: An experimental and computational study
Herkert, Lorena,Green, Samantha L. J.,Barker, Graeme,Johnson, David G.,Young, Paul C.,Macgregor, Stuart A.,Lee, Ai-Lan
, p. 11540 - 11548 (2014)
A gold(I)-catalysed direct thioetherification reaction between allylic alcohols and thiols is presented. The reaction is generally highly regioselective (SN2′). This dehydrative allylation procedure is very mild and atom economical, producing o
Multicatalytic Stereoselective Synthesis of Highly Substituted Alkenes by Sequential Isomerization/Cross-Coupling Reactions
Romano, Ciro,Mazet, Clément
supporting information, p. 4743 - 4750 (2018/04/10)
Starting from readily available alkenyl methyl ethers, the stereoselective preparation of highly substituted alkenes by two complementary multicatalytic sequential isomerization/cross-coupling sequences is described. Both elementary steps of these sequences are challenging processes when considered independently. A cationic iridium catalyst was identified for the stereoselective isomerization of allyl methyl ethers and was found to be compatible with a nickel catalyst for the subsequent cross-coupling of the in situ generated methyl vinyl ethers with various Grignard reagents. The method is compatible with sensitive functional groups and a multitude of olefinic substitution patterns to deliver products with high control of the newly generated C=C bond. A highly enantioselective variant of this [Ir/Ni] sequence has been established using a chiral iridium precatalyst. A complementary [Pd/Ni] catalytic sequence has been optimized for alkenyl methyl ethers with a remote C=C bond. The final alkenes were isolated with a lower level of stereocontrol. Upon proper choice of the Grignard reagent, we demonstrated that C(sp2) - C(sp2) and C(sp2) - C(sp3) bonds can be constructed with both systems delivering products that would be difficult to access by conventional methods.
Chirality Transfer in Gold(I)-Catalysed Direct Allylic Etherifications of Unactivated Alcohols: Experimental and Computational Study
Barker, Graeme,Johnson, David G.,Young, Paul C.,Macgregor, Stuart A.,Lee, Ai-Lan
, p. 13748 - 13757 (2015/09/22)
Gold(I)-catalysed direct allylic etherifications have been successfully carried out with chirality transfer to yield enantioenriched, γ-substituted secondary allylic ethers. Our investigations include a full substrate-scope screen to ascertain substituent effects on the regioselectivity, stereoselectivity and efficiency of chirality transfer, as well as control experiments to elucidate the mechanistic subtleties of the chirality-transfer process. Crucially, addition of molecular sieves was found to be necessary to ensure efficient and general chirality transfer. Computational studies suggest that the efficiency of chirality transfer is linked to the aggregation of the alcohol nucleophile around the reactive π-bound Au-allylic ether complex. With a single alcohol nucleophile, a high degree of chirality transfer is predicted. However, if three alcohols are present, alternative proton transfer chain mechanisms that Erode the efficiency of chirality transfer become competitive.
Pd-catalyzed regioselective and stereospecific Suzuki-Miyaura coupling of allylic carbonates with arylboronic acids
Li, Chenguang,Xing, Juxiang,Zhao, Jingming,Huynh, Patrick,Zhang, Wanbin,Jiang, Pingkai,Zhang, Yong Jian
supporting information; experimental part, p. 390 - 393 (2012/02/15)
The Pd-catalyzed Suzuki-Miyaura coupling reaction of unsymmetric 1,3-disubstituted secondary allylic carbonates with arylboronic acids has been developed in a wet solvent under a base-free system to afford allyl-aryl coupling products in a high level of isolated yields with complete regio- and E/Z-selectivities with good to excellent chemoselectivities. The coupling reaction of optically active allyl carbonates gave allyl-aryl coupling products with excellent enantioselectivities with inversion of the stereochemistry. This coupling method was successfully applied to the synthesis of (S)-naproxen.
Copper-catalyzed enantioselective 1,4-addition to α,β- unsaturated aldehydes
Palais, Laetitia,Babel, Lucille,Quintard, Adrien,Belot, Sebastien,Alexakis, Alexandre
supporting information; experimental part, p. 1988 - 1991 (2010/07/10)
Figure presented The first asymmetric Cu-catalyzed conjugate addition of dialkylzinc zinc reagents to a large scope of enals in presence of phosphoramidite, SimplePhos, or (R)-BINAP ligands with enantiomeric excesses up to 90% is reported. Moreover, ACA of Grignard reagents afforded moderate to good 1,4-regioselectivities with enantioselectivities up to 90%.
Cobalt(II)-Catalyzed Conversion of Allylic Alcohols/Acetates to Allylic Amides in the Presence of Nitriles
Mukhopadhyay, Manoj,Reddy, M. Madhava,Maikap, G. C.,Iqbal, Javed
, p. 2670 - 2676 (2007/10/02)
Various secondary allylic alcohols or their acetates and tertiary allylic alcohols can be converted to the corresponding transposed allylic amides in the presence of a catalytic quantity of cobalt(II) chloride and acetic anhydride in acetonitrile.Tertiary alcohols undergo complete rearrangement whereas secondary ones afford a mixture of regioisomers.Moderate yields of amides are also obtained by reacting acrylonitrile with secondary alcohols in 1,2-dichloroethane.The presence of acetic anhydride or acetic acid is crucial to the formation of amides as the absence of the former affords no amides and the allylic alcohols are mainly recovered as regioisomeric mixtures.The regioselectivity during amide formation can be enhanced by using cobalt complexes 14-16 in acetic acid medium.Some preliminary studies indicate that these reactions are proceeding via an ?-allyl complex or tight ion pair rather than a sigmatropic rearrangement of acetamidate obtained in a Pinner reaction.
Concomitant Epoxide Deoxygenation and Deacetylation of Glycidyl Acetates Induced by Telluride Ion
Dittmer, Donald C.,Zhang, Yanzhi,Discordia, Robert P.
, p. 1004 - 1010 (2007/10/02)
Treatment of glycidyl acetates with telluride ion (Te(2-)) produced by reduction of elemental Te with LiEt3BH yields allylic alcohols by loss of the epoxide oxygen atom and the acetyl group from the ester.If the glycidyl acetate is disubstituted at C-3, a rearrangement to an isomeric allylic alcohol competes with the deoxygenation-deacetylation.Triethylborane, a byproduct in the reduction of Te, is believed to play an important role as a Lewis acid since when it is absent or removed by addition of fluoride ion the reaction is extremely slow.
A Tellurium Transposition Route to Allylic Alcohols: Overcoming Some Limitations of the Sharpless-Katsuki Asymmetric Epoxidation
Dittmer, Donald C.,Discordia, Robert P.,Zhang, Yanzhi,Murphy, Christopher K.,Kumar, Archana,et al.
, p. 718 - 731 (2007/10/02)
Good yields of enantiomeric allylic alcohols can be obtained in high enantiomeric excess (ee) by combining Sharpless-Katsuki asymmetric epoxidation process (SAE) with tellurium chemistry.The advantages of the tellurium process are as follows: (1) the 50percent yield limitation on the allylic alcohol in the Sharpless kinetic resolution (SKR) can be overcome; (2) allylic tertiary alcohols which are unsatisfactory substrates in the SKR can be obtained in high optical purity; (3) optically active secondary allylic alcohols with tertiary alkyl substituents (e.g. tert-butyl) at C-1 can be obtained in high ee; (4) optically active sterically congested cis secondary alcohols can be obtained in high ee; and (5) the nuisance of the slow SAE of some vinyl carbinols can be avoided.The key step in the reaction sequence is either a stereospecific 1,3-transposition of double bond and alcohol functionalities or an inversion of the alcohol configuration with concomitant deoxygenation of the epoxide function in epoxy alcohols.Trans secondary allylic alcohols can be converted to cis secondary allylic alcohols by way of erythro epoxy alcohols (glycidols); threo glycidyl derivatives are converted to trans secondary allylic alcohols.These transformations are accomplished by the action of telluride ion, generated in situ from the element, on a glycidyl sulfonate ester.Reduction of elemental Te is conveniently done with rongalite (HOCH2SO2Na) in an aqueous medium.This method is satisfactory when Te2- is required to attack at primary carbon site of a glycidyl sulfonate.In cases where Te2- is required to attack a secondary carbon site, reduction of the tellurium must be done with NaBH4 or LiEt3BH.Elemental tellurium is precipitated during the course of the reactions and can be recovered and reused.
Telluride-mediated stereospecific conversion of racemic E-allylic alcohols to homochiral Z-allylic alcohols; transposition of primary and secondary allylic alcohols via glycidol derivatives
Discordia, Robert P.,Murphy, Christopher K.,Dittmer, Donald C.
, p. 5603 - 5606 (2007/10/02)
Racemic trans-secondary allylic alcohols can be converted to homochiral cis-secondary allylic alcohols by means of a telluride-mediated transposition reaction applied to the homochiral glycidol obtained from a Sharpless kinetic resolution. (+)-Linalool is obtained in>95% enantiomeric excess from geraniol, an example of a transposition of a primary allylic alcohol to a homochiral tertiary alcohol.
