17772-45-1Relevant academic research and scientific papers
Direct Allylic C(sp3)?H and Vinylic C(sp2)?H Thiolation with Hydrogen Evolution by Quantum Dots and Visible Light
Huang, Cheng,Ci, Rui-Nan,Qiao, Jia,Wang, Xu-Zhe,Feng, Ke,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
supporting information, p. 11779 - 11783 (2021/04/21)
Direct allylic C?H thiolation is straightforward for allylic C(sp3)?S bond formation. However, strong interactions between thiol and transition metal catalysts lead to deactivation of the catalytic cycle or oxidation of sulfur atom under oxidative condition. Thus, direct allylic C(sp3)?H thiolation has proved difficult. Represented herein is an exceptional for direct, efficient, atom- and step-economic thiolation of allylic C(sp3)?H and thiol S?H under visible light irradiation. Radical trapping experiments and electron paramagnetic resonance (EPR) spectroscopy identified the allylic radical and thiyl radical generated on the surface of photocatalyst quantum dots (QDs). The C?S bond formation does not require external oxidants and radical initiators, and hydrogen (H2) is produced as byproduct. When vinylic C(sp2)?H was used instead of allylic C(sp3)?H bond, the radical-radical cross-coupling of C(sp2)?H and S?H was achieved with liberation of H2. Such a unique transformation opens up a door toward direct C?H and S?H coupling for valuable organosulfur chemistry.
Atom-efficient vinylic arylations with triarylbismuths as substoichiometric multicoupling reagents under palladium catalysis
Rao, Maddali L.N.,Jadhav, Deepak N.,Venkatesh, Varadhachari
experimental part, p. 4300 - 4306 (2011/02/24)
The first atom-efficient arylation of vinylic iodides was achieved by using triarylbismuths as substoichiometric multicoupling reagents under palladium catalysis. Vinylic iodides were efficiently coupled with electronically divergent triarylbismuths to furnish the corresponding arylated products in short reaction times.
The first ligand-modulated oxidative Heck vinylation. Efficient catalysis with molecular oxygen as palladium(0) oxidant
Andappan, Murugaiah M. S.,Nilsson, Peter,Larhed, Mats
, p. 218 - 219 (2007/10/03)
The discovery of the first ligand-supported Pd(II) catalysed oxidative Heck reaction with molecular oxygen as reoxidant and the scope with diverse arylboronic acids and olefins using only 1-2% of catalyst are reported.
On the regioselectivity of palladium catalyzed cross-coupling reactions of alkenylsilanes: participation of β-cationic organosilicate-palladium species during the transmetallation
Hatanaka, Yasuo,Goda, Ken-ichi,Hiyama, Tamejiro
, p. 97 - 100 (2007/10/02)
The cross-coupling reaction promoted by a palladium catalyst and fluoride salt of 1--1-phenylethene (1) with substituted aryl iodides gave the unexpected cine-substitution products (E)-1-aryl-2-phenylethenes (3) along with the normal ipso-substitution product 1-aryl-1-phenylethene (2).The product ratios were strongly dependent on the electronic nature of the substituent on aryl iodides: ipso-substitution products (2) were favoured by an electron-withdrawing substituent, and cine-substitution products (3) by an electron-donating substituent.On the basis of these observations, the following mechanism of transmetallation of alkenyl(fluoro)silicates with arylpalladium is proposed: electrophilic attack of an arylpalladium complex on the olefinic α-carbon of an alkenyl(fluoro)silicate produces a β-cationic organosilicate-palladium species which then transfers the alkenyl group from silicon to the palladium complex. Key words: Silane; Palladium; Transmetallation; Regioselectivity
