92075-81-5Relevant academic research and scientific papers
Enantioselective Radical Carbocyanation of 1,3-Dienes via Photocatalytic Generation of Allylcopper Complexes
Lu, Fu-Dong,Lu, Liang-Qiu,He, Gui-Feng,Bai, Jun-Chuan,Xiao, Wen-Jing
supporting information, p. 4168 - 4173 (2021/04/06)
1,3-Dienes are readily available feedstocks that are widely used in the laboratory and industry. However, the potential of converting 1,3-dienes into value-Added products, especially chiral products, has not yet been fully exploited. By synergetic photoredox/copper catalysis, we achieve the first visible-light-induced, enantioselective carbocyanation of 1,3-dienes by using carboxylic acid derivatives and trimethylsilyl cyanide. Under mild and neutral conditions, a diverse range of chiral allyl cyanides are produced in generally good efficiency and with high enantioselectivity from bench-stable and user-safe chemicals. Moreover, preliminary results also confirm that this success can be expanded to 1,3-enynes and the four-component carbonylative carbocyanation of 1,3-dienes and 1,3-enynes.
Highly efficient kinetic resolution of aryl-alkenyl alcohols by ru-catalyzed hydrogen transfer
Jin, Ming Yu,Tao, Guanyu,Xing, Xiangyou,You, Yipeng
supporting information, (2021/12/24)
No matter through asymmetric reduction of ketones or kinetic resolution of secondary alcohols, enantioselective synthesis of the corresponding secondary alcohols is challenging when the two groups attached to the prochiral or chiral centers are spatially
H-*BEA Zeolite-Catalyzed Nucleophilic Substitution in Allyl Alcohols Using Sulfonamides, Amides, and Anilines
Aoki, Shunsuke,Fujii, Takeshi,Morita, Sachiko,Nishida, Ryo,Ohtsuki, Akimichi,Okumura, Kazu
, (2020/07/24)
Herein, we report a novel zeolite-catalyzed nucleophilic substitution in allyl alcohols. The product yield was improved upon the addition of NaOTf (0.05 mol-percent) using the studied zeolites. The highest yields were observed using H-*BEA(Si/Al2 = 40)/NaOTf. The scope of the reaction with respect to the nucleophile was examined using 1,3-diphenylprop-2-ene-1-ol as a model substrate under optimized reaction conditions. p-Substituted aryl sulfonamides bearing electron-rich or electron-deficient substituents, alkyl sulfonamides, and heteroaryl sulfonamides undergo the amidation reaction to produce their corresponding allyl sulfonamides in good yield. Amides and anilines exhibited low activity under the optimized conditions, however, performing the reaction at 90 °C produced the target product. The scope of the allyl alcohol was investigated using p-toluenesulfonamide as the nucleophile and the reaction proceeded with a variety of allylic alcohols. To probe the practical utility of the H-*BEA-catalyzed amidation reaction, a gram-scale reaction was performed using 1.01 g (4.8 mmol) of allyl alcohol, which afforded the target product in 88 percent yield.
Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones
Beltran, Frédéric,Bergamaschi, Enrico,Funes-Ardoiz, Ignacio,Teskey, Christopher J.
, p. 21176 - 21182 (2020/09/17)
Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their “hard” or “soft” character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of α,β-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.
Synthesis of a Bolm's 2,2′-Bipyridine Ligand Analogue and Its Applications
Bedná?ová, Eva,Dra?ínsky, Martin,Malatinec, ?tefan,Císa?ová, Ivana,Lamaty, Frédéric,Kotora, Martin
supporting information, p. 2869 - 2878 (2018/08/17)
A new method of synthesis of an analogue of Bolm's 2,2′-bipyridine ligand based on the catalytic [2+2+2] cyclotrimerization of 1-halodiynes with nitriles was developed. Crucial step of the whole synthesis turned out to be homodimerization of a substituted 2-bromopyridine to the corresponding bipyridine, that was studied and optimized. The newly prepared bipyridine (S,S)-2 was then tested as a chiral ligand in metal-catalyzed enantioselective reactions. Out of the studied reactions the most promising results were obtained in epoxide ring opening (82% yield, 98% ee) and Mukaiyama aldol reaction (>96% yield, 99/1 dr, 92% ee). In the case of Mukaiyama-aldol reaction as well as in the Michael addition, novel ligand 2 proved its robustness compared to Bolm's ligand as it was less sensitive to the purity of used reagents. (Figure presented.).
Copper-Catalyzed Enantioselective Conjugate Addition to α,β-Unsaturated Aldehydes with Various Organometallic Reagents
Goncalves-Contal, Sylvie,Gremaud, Ludovic,Palais, La?titia,Babel, Lucille,Alexakis, Alexandre
, p. 3301 - 3308 (2016/09/12)
β-Substituted aldehydes constitute a very important class of compounds found in nature. Synthesis of this motif can be envisioned by C-C bond formation on enals. For this purpose, we report herein the development of enantioselective copper-catalyzed conjugate addition of various organometallic reagents to α,β-unsaturated aldehydes with (R)-H8BINAP, (R)-TolBINAP, and (R)-SEGPHOS as chiral ligands. Three sets of conditions were successfully developed and several enals were used. Reactivity and regio- and enantioselectivities were strongly dependent on reaction conditions and substrates. Good to excellent regio- and enantioselectivities were obtained with zinc reagents R2Zn and aluminum reagents R3Al. However, the asymmetric conjugate addition of Grignard reagents afforded only moderate to good regio- and enantioselectivities.
A monolith immobilised iridium Cp catalyst for hydrogen transfer reactions under flow conditions
Rojo, Maria Victoria,Guetzoyan, Lucie,Baxendale, Ian. R.
, p. 1768 - 1777 (2015/02/19)
An immobilised iridium hydrogen transfer catalyst has been developed for use in flow based processing by incorporation of a ligand into a porous polymeric monolithic flow reactor. The monolithic construct has been used for several redox reductions demonstrating excellent recyclability, good turnover numbers and high chemical stability giving negligible metal leaching over extended periods of use.
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
supporting information, 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.
Enantiospecific, nickel-catalyzed cross-couplings of allylic pivalates and arylboroxines
Srinivas, Harathi D.,Zhou, Qi,Watson, Mary P.
supporting information, p. 3596 - 3599 (2014/07/21)
We have developed an enantiospecific, nickel-catalyzed cross-coupling of unsymmetric 1,3-disubstituted allylic pivalates with arylboroxines. The success of this reaction relies on the use of BnPPh2 as a supporting ligand for the nickel(0) catalyst and NaOMe as a base. This method shows excellent functional group tolerance and broad scope in both the allylic pivalate and arylboroxine, enabling the preparation of 1,3-diaryl allylic products in high yields with excellent levels of regioselectivity and stereochemical fidelity.
Structural study-guided development of versatile phase-transfer catalysts for asymmetric conjugate additions of cyanide
Provencher, Brian A.,Bartelson, Keith J.,Liu, Yan,Foxman, Bruce M.,Deng, Li
supporting information; experimental part, p. 10565 - 10569 (2011/12/05)
Unprecedented phase-transfer catalysts for the first example of an organocatalytic asymmetric conjugate addition of cyanide with acetone cyanohydrin are reported (see scheme). Utilizing an accessible cupreidinium salt and a cyanation reagent suitable for industrial scale, this reaction holds significant promise for practical asymmetric synthesis. The catalysts were developed as a result of key structural insights gained by X-ray analysis. Copyright
