42879-13-0Relevant academic research and scientific papers
Electrochemical Hydrogenation with Gaseous Ammonia
Li, Jin,He, Lingfeng,Liu, Xu,Cheng, Xu,Li, Guigen
supporting information, p. 1759 - 1763 (2019/01/16)
As a carbon-free and sustainable fuel, ammonia serves as high-energy-density hydrogen-storage material. It is important to develop new reactions able to utilize ammonia as a hydrogen source directly. Herein, we report an electrochemical hydrogenation of alkenes, alkynes, and ketones using ammonia as the hydrogen source and carbon electrodes. A variety of heterocycles and functional groups, including for example sulfide, benzyl, benzyl carbamate, and allyl carbamate were well tolerated. Fast stepwise electron transfer and proton transfer processes were proposed to account for the transformation.
Stereochemical course of baker's yeast mediated reduction of the tri- and tetrasubstituted double bonds of substituted cinnamaldehydes
Fronza, Giovanni,Fuganti, Claudio,Serra, Stefano
experimental part, p. 6160 - 6171 (2010/03/24)
A comprehensive study of the stereochemical course of baker's yeast mediated reduction of substituted cinnamaldehydes is reported. Hydride addition to the β position of β-methylcinnamaldehydes preferentially afforded isomers of (3S)-3-phenylbutan-1-ol. The reduction of (E)-2,3-dimethyl- cinnamaldehyde (15) produced a mixture of (2S,3S)- and (2R,3S)-2-methyl-3- phenylbutan-1-ol (13 and 14), respectively, with 93 % ee. Conversely (Z)-2,3-dimethylcinnamal-dehyde (16) afforded, a mixture of 13 and 14 with 33 % ee. Accordingly, the reduction of trisubstituted β-methylcinnam-aldehydes 34 and 35 proceeded with the same stereochemical preference and with higher enantioselectivity to give (S) 3-phenylbutan-1-ol (37). In addition, deuterium, incorporation and 2H NMR studies demonstrated that the addition of the second hydrogen atom to the a position proceeded with very low stereochemical control and the overall process is formally a mixture of cis/trans hydrogen addition to the double bond. Alternatively, α-methylcinnamaldehyde is reduced to (S)-2-methyl-3-phenylpropan-1-ol (24) with preferential addition of the hydride to the opposite β face with good stereochemical control of the irons addition of hydrogen to the double bond. Wiley-VCH Verlag GmbH & Co. KGaA.
Stereoselective Hydrogen Transfer Reactions Involving Acyclic Radicals. Tandem Substituted Tetrahydrofuran Formation and Stereoselective Reduction: Synthesis of the C17-C22 Subunit of Ionomycin
Guindon, Y.,Yoakim, C.,Gorys, V.,Ogilvie, W. W.,Delorme, D.,et al.
, p. 1166 - 1178 (2007/10/02)
The tandem iodoetherification reaction and stereoselective reduction of acyclic redicals has been used in the stereocontrolled synthesis of substituted tetrahydrofurans.Such a tetrahydrofuran intermediate is regioselectively cleaved using Me2BBr to reveal
The effect of polar substituents on the conformation and stereochemistry of enolate radicals
Giese,Damm,Wetterich,Zeitz,Rancourt,Guindon
, p. 5885 - 5888 (2007/10/02)
ESR measurements and AM1 calculations show that ester substituted radicals 2 and 6 prefer conformation A as a result of allylic strain effects. But dipolar repulsion between substituents X and CO2Et In 2 and 6 has a pronounced effect on the con
STEREOSELECTIVE REDUCTION OF ACYCLIC α-BROMO ESTERS
Guindon, Y.,Yoakim, C.,Lemieux, R.,Boisvert, L.,Delorme, D.,Lavallee, J.-F.
, p. 2845 - 2848 (2007/10/02)
Radical-based reduction of β-methoxy-or β-fluoro-α-bromo esters could be achieved with good stereoselection at low temperatures.A systematic evaluation of this reaction is presented and possible transition state models are discussed.
