26567-82-8Relevant academic research and scientific papers
Pd-catalyzed Oxidative Cross-coupling of Alkyl Chromium(0) Fischer Carbene Complexes with Organoboronic Acids
Wang, Kang,Yang, Jinghui,Yao, Xingqi,Wang, Jianbo
supporting information, p. 3165 - 3168 (2018/10/15)
Alkyl chromium(0) carbene complexes have been explored as the cross-coupling partners in the palladium-catalyzed reaction with aryl or alkenyl boronic acids. This coupling reaction displays the versatile reactivities of alkyl chromium(0) carbenes under palladium catalysis. Mechanistically, this transformation is proposed to involve deprotonation of the alkyl chromium carbene substrate to generate a vinyl chromium anion intermediate that undergoes transmetalation to organopalladium species and reductive elimination.
Z-selective, anti-Markovnikov addition of alkoxides to terminal alkynes: An electron transfer pathway?
Cuthbertson, James,Wilden, Jonathan D.
, p. 4385 - 4392 (2015/06/08)
Potassium alkoxides undergo anti-Markovnikov addition to aryl-substituted alkynes with Z selectivity in DMF as the solvent. The yields and efficiency of the reaction was also found to be enhanced by the addition of a secondary amine ligand such as N,N′-di
Product studies and laser flash photolysis on alkyl radicals containing two different β-leaving groups are consonant with the formation of an olefin cation radical
Bales,Horner,Huang,Newcomb,Crich,Greenberg
, p. 3623 - 3629 (2007/10/03)
1-Bromo-2-methoxy-1-phenylpropan-2-yl (3) and 2-methoxy-1-phenyl-1-diphenylphosphatopropan-2-yl (4) were generated under continual photolysis from the respective PTOC precursors in a mixture of acetonitrile and methanol. The radicals undergo heterolytic fragmentation of the substituent in the β-position to generate the olefin cation radical (5). Z-2-Methoxy-1-phenylpropene (15) is the major product formed in the presence of 1,4-cyclohexadiene, and is believed to result from hydrogen atom transfer to the oxygen of the olefin cation radical, followed by deprotonation. Laser flash photolysis experiments indicate that reaction between 5 and 1,4-cyclohexadiene occurs with a rate constant of ～6 × 105 M-1 s-1. 2,2-Dimethoxy-1-phenylpropane (18) is observed as a minor product. Laser flash photolysis experiments place an upper limit on methanol trapping of 5 at k 3 M-1 s-1 and do not provide any evidence for the formation of reactive intermediates other than 5. The use of two PTOC precursors containing different leaving groups to generate a common olefin cation radical enables one to utilize product analysis to probe for the intermediacy of other reactive intermediates. The ratio of 15:18 is dependent upon hydrogen atom donor concentration, but is independent of the PTOC precursor. These observations are consistent with the proposal that both products result from trapping of 5 that is formed via heterolysis of 3 and 4.
Thermal and photochemical solvolysis of (E)- and (Z)-2-phenyl-1-propenyl(phenyl)iodonium tetrafluoroborate: Benzenium and primary vinylic cation intermediates
Gronheid,Lodder,Ochiai,Sueda,Okuyama
, p. 8760 - 8765 (2007/10/03)
The thermal and photochemical solvolysis of the two stereoisomeric 2-phenyl-1-propenyl(phenyl)-iodonium tetrafluoroborates has been investigated in alcoholic solvents of varying nucleophilicity. The product profiles and rates of product formation in the thermal reaction are all compatible with a mechanism involving cleavage of the vinylic C - I bond assisted by the group in the trans position (methyl or phenyl), always leading to rearranged products. Depending on the nucleophilicity of the solvent, the primarily formed cations may or may not further rearrange to more stable isomers. The less reactive Z compound also yields some unrearranged vinyl ether product in the more nucleophilic solvents via an in-plane SN2 mechanism. The mechanism of the photolysis involves direct, unassisted cleavage of the vinylic, and aromatic, C - I bond in an SN1 mechanism. This produces a primary vinyl cation, which is partially trapped prior to rearrangement in methanol. The unrearranged vinyl ethers are mainly formed with retention of configuration via a λ3-iodonium/solvent complex in an SNi mechanism. Thermal and photochemical solvolyses of iodonium salts are complementary techniques for the generation of different cation intermediates from the same substrate.
