593-08-8Relevant academic research and scientific papers
REVERSIBLE PROTONATION OF A VINYL SELENIDE DURING ITS ACID CATALYZED HYDROLYSIS
Piquard, J. L.,Hevesi, L.
, p. 1901 - 1902 (1980)
Partially reversible protonation is shown to occur in the course of the acid catalyzed hydrolysis of 2-methylseleno-2 tridecene 1 together with a significant lowering of the kinetic solvent isotope effect (kH2O+/kD2O+= 1.4).
Oxidative Cleavage of Alkenes by O2with a Non-Heme Manganese Catalyst
Bennett, Elliot L.,Brookfield, Adam,Guan, Renpeng,Huang, Zhiliang,Mcinnes, Eric J. L.,Robertson, Craig M.,Shanmugam, Muralidharan,Xiao, Jianliang
supporting information, p. 10005 - 10013 (2021/07/19)
The oxidative cleavage of C═C double bonds with molecular oxygen to produce carbonyl compounds is an important transformation in chemical and pharmaceutical synthesis. In nature, enzymes containing the first-row transition metals, particularly heme and non-heme iron-dependent enzymes, readily activate O2 and oxidatively cleave C═C bonds with exquisite precision under ambient conditions. The reaction remains challenging for synthetic chemists, however. There are only a small number of known synthetic metal catalysts that allow for the oxidative cleavage of alkenes at an atmospheric pressure of O2, with very few known to catalyze the cleavage of nonactivated alkenes. In this work, we describe a light-driven, Mn-catalyzed protocol for the selective oxidation of alkenes to carbonyls under 1 atm of O2. For the first time, aromatic as well as various nonactivated aliphatic alkenes could be oxidized to afford ketones and aldehydes under clean, mild conditions with a first row, biorelevant metal catalyst. Moreover, the protocol shows a very good functional group tolerance. Mechanistic investigation suggests that Mn-oxo species, including an asymmetric, mixed-valent bis(μ-oxo)-Mn(III,IV) complex, are involved in the oxidation, and the solvent methanol participates in O2 activation that leads to the formation of the oxo species.
Highly productive α-alkylation of ketones with alcohols mediated by an Ir-oxalamidato/solid base catalyst system
Maeda, Hironori,Nara, Hideki,Shimizu, Hideo
supporting information, p. 2772 - 2779 (2020/12/29)
An Ir-oxalamidato complex in combination with a solid base (e.g., magnesium aluminometasilicate/Ca(OH)2) significantly improved the catalyst productivity in α-alkylation of methyl ketones with primary alcohols. Optimization through systematic variation of the oxalamidato ligand led to a practical turnover number (TON) of 10 000.40 000.
Mild Deprotection of Dithioacetals by TMSCl/NaI Association in CH3CN
Yao, Yunxin,Zhao, Guangkuan,Hamze, Abdallah,Alami, Mouad,Provot, Olivier
, p. 5775 - 5779 (2020/08/17)
A mild process using a combination of TMSCl and NaI in acetonitrile is used to regenerate carbonyl compounds from a variety of dithiane and dithiolane derivatives. This easy to handle and inexpensive protocol is also efficient to deprotect oxygenated and mixed acetals as 1,3-dioxanes, 1,3-dioxolanes and 1,3-oxathianes quantitatively. As a possible extension of this method, it was also shown that nitrogenated substrates such as hydrazones, N-tosylhydrazones, and ketimines reacted well under these conditions to give the expected ketones in high yields. The methodology proposed herein is a good alternative to the existing methods since it does not use metals, oxidants, reducing agents, acidic or basic media, and keto-products were obtained in high to excellent yields.
Nickel/Photoredox-Catalyzed Methylation of (Hetero)aryl Chlorides Using Trimethyl Orthoformate as a Methyl Radical Source
Kariofillis, Stavros K.,Shields, Benjamin J.,Tekle-Smith, Makeda A.,Zacuto, Michael J.,Doyle, Abigail G.
supporting information, p. 7683 - 7689 (2020/04/22)
Methylation of organohalides represents a valuable transformation, but typically requires harsh reaction conditions or reagents. We report a radical approach for the methylation of (hetero)aryl chlorides using nickel/photoredox catalysis wherein trimethyl orthoformate, a common laboratory solvent, serves as a methyl source. This method permits methylation of (hetero)aryl chlorides and acyl chlorides at an early and late stage with broad functional group compatibility. Mechanistic investigations indicate that trimethyl orthoformate serves as a source of methyl radical via β-scission from a tertiary radical generated upon chlorine-mediated hydrogen atom transfer.
Hydrofunctionalization of Olefins to Higher Aliphatic Alcohols via Visible-Light Photocatalytic Coupling
Bao, Jingxian,Fan, Yonghui,Zhang, Shuyi,Zhong, Liangshu,Wu, Minghong,Sun, Yuhan
, (2019/04/14)
Abstract: An atomically economical green protocol for the hydrofunctionalization of olefins to higher aliphatic alcohols with 100% anti-Markovnikov regioselectivity was developed via visible-light photocatalytic coupling. This method employs cheap, readily available and abundant methanol as both the C1 feedstock and the hydrogen source under visible light irradiation over CdS photocatalyst. A wide scope of olefin substrates could be hydrofunctionalized successfully to the corresponding higher alcohols with high selectivity. Besides alcohol, acetone and acetonitrile can also couple with olefins to generate the corresponding hydrofunctionalization products, suggesting promising potential industrial application. Graphical Abstract: [Figure not available: see fulltext.] Hydrofunctionalization of olefins to value-added chemicals with high selectivity was achieved via visible-light photocatalytic cross-coupling.
Hydrogen-transfer reduction of α,β-unsaturated carbonyl compounds catalyzed by naphthyridine-functionalized N-heterocyclic carbene complexes
Huang, Hsiao-Ching,Ramanathan, Mani,Liu, Yi-Hong,Peng, Shie-Ming,Liu, Shiuh-Tzung
, (2017/07/25)
Substitution of silver complex of 2-chloro-7-(mesitylimidazolylidenylmethyl)naphthyridine (NpNHC) with palladium(II), rhodium(I) and iridium(I) metal precursors provided [Pd(C,N-NpNHC)(η3-allyl)](BF4) (5), RhCl(COD)(C-NpNHC) (6a) and IrCl(COD)(C-NpNHC) (6b), respectively. Abstraction of chloride from 6a and 6b with AgBF4 provided the chelation complexes [Rh(COD)(C,N-NpNHC)](BF4) (7a) and Ir(COD)(C,N-NpNHC)(BF4) (7b), respectively. All complexes were characterized using NMR and elemental analyses and the structural details of 5 and 6a were further confirmed using X-ray crystallography. In catalytic activity studies, complex 5 was found to be an effective catalyst in the hydrogen-transfer reduction of α,β-unsaturated carbonyl compounds into the corresponding saturated carbonyl compounds.
Iodine monochloride (ICl) as a highly efficient, green oxidant for the oxidation of alcohols to corresponding carbonyl compounds
Wei, Peng,Zhang, Datong,Gao, Zhigang,Cai, Wenqing,Xu, Weiren,Tang, Lida,Zhao, Guilong
supporting information, p. 1457 - 1470 (2015/05/20)
Iodine monochloride (ICl) was discovered to be a highly efficient, green oxidant, which can oxidize aldose hemiacetals, diarylmethanols, arylalkylmethanols, anddialkylmethanols to the corresponding aldose lactones, diarylmethanones, arylalkylmethanones, and dialkylmethanones, respectively, in high yields. ICl as a green, metal-free oxidant is characterized by mild reaction condition, short reaction time, good yield, and broad scope.
1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
-
, (2015/03/03)
The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
-
, (2015/03/03)
The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
