- Iron-catalyzed arene C-H hydroxylation
-
The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
- Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
-
-
- Structure-Odor Activity Studies on Derivatives of Aromatic and Oxygenated Monoterpenoids Synthesized by Modifying p-Cymene
-
Thymoquinone was recently reported as having a unique pencil-like odor and being the impact compound for the cedar-like and cedar wood-based product smell such as pencils. The compounds thymol and carvacrol are structurally related odorants commonly found in plants and foods such as thyme and oregano, also having a significant contribution to their overall aroma. However, a systematic elucidation of the sensory properties in this class of oxygenated, aromatic monoterpenoids has not been carried out. To close this gap and gain new insights into structure-odor relationships leading to pencil-like and woody odors, 19 structurally related derivatives of p-cymene starting from thymol and carvacrol were synthesized and characterized. The compounds had odor thresholds ranging from 2.0 ng/L air to 388.8 ng/L air, being lowest for thymol and carvacrol and highest for thymohydroquinone. The compounds smelled mostly thyme-like, oregano-like, and pencil-like with phenolic, earthy, and medicinal variations in their odor character, which could be successfully linked to structural motifs.
- Schreiner, Linda,Bauer, Johannes,Ortner, Eva,Buettner, Andrea
-
supporting information
p. 834 - 842
(2020/03/30)
-
- A biomimetic approach towards phorone sesterterpenoids
-
We report an investigation towards a unified total synthesis of the Korean sponge derived sesterterpenoids, phorones A (1) and B (2), via a biomimetic strategy. This work has established a new synthetic strategy to the parent ansellane sesterterpenoid ske
- Shirley, Harry J.,Bray, Christopher D.
-
p. 6985 - 6988
(2019/08/01)
-
- Palladium-catalyzed hydroxylation of aryl and heteroaryl halides enabled by the use of a palladacycle precatalyst
-
A method for the hydroxylation of aryl and heteroaryl halides, promoted by a catalyst based on a biarylphosphine ligand tBuBrettPhos (L5) and its corresponding palladium precatalyst (1), is described. The reactions allow the cross-coupling of both potassium and cesium hydroxides with (hetero)aryl halides to afford a variety of phenols and hydroxylated heteroarenes in high to excellent yield.
- Cheung, Chi Wai,Buchwald, Stephen L.
-
p. 5351 - 5358
(2014/06/23)
-
- 3-BENZYLOXYPHENYLOXOACETIC ACID COMPOUNDS FOR REDUCING URIC ACID
-
Uric acid in mammalian subjects is reduced and excretion of uric acid is increased by administering a compound of Formula (I) or its pharmaceutically acceptable salts. The uric acid-lowering effects of the compounds of this invention are used to treat or
- -
-
-
- OXIME ETHER DERIVATIVE AND BACTERICIDE FOR AGRICULTURAL AND HORTICULTURAL USE
-
Provided is a fungicide for agriculture and horticulture containing at least one of oxime ether derivative represented by Formula (I) or a salt thereof (wherein X represents a halogen atom, a C1-C20 alkyl group or the like, R1 and R2
- -
-
-
- Efficient total synthesis of racemic bisabolane sesquiterpenes curcuphenol and xanthorrhizol starting from substituted acetophenones
-
A total synthesis of natural bisabolane sesquiterpenes curcuphenol (1) and xanthorrhizol (2) was developed by using the substituted acetophenones 4 and 5, respectively, as starting materials. The acetyl group of the latter was activated through ethoxycarb
- Montiel, Luisa E.,Zepeda, L. Gerardo,Tamariz, Joaquin
-
experimental part
p. 1261 - 1273
(2010/09/07)
-
- Synthesis of Aromatic Monoterpenyl Geranyl Ethers as Possible Insect Juvenile Hormon Mimics
-
Substituted phenyl geranyl (IX-XV, XXIV-XXVIII) and 7-methoxygeranyl ethers (XVI-XXIII, XXVIII) have been synthesised as possible juvenile hormon (JH) mimics.Out of these ethers only XVII, XVIII and XXIII show low JH activity.
- Phadnis, A. P.,Nanda, B.,Patwardhan, Sarita A.,Gupta, A. S.
-
p. 1098 - 1102
(2007/10/02)
-
- ipso Nitration. XXIII. Reactions of cyclohexadiene adducts from nitration of 4-ethyltoluene in acetic anhydride
-
The diastereoisomers of 4-ethyl-1-methyl-4-nitrocyclohexa-2,5-dienyl acetate (1) and 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetate (2) are stereospecifically reduced to the corresponding nitrocyclohexadienols with aluminum hydride.Each dienol is stereospecifically methylated to the corresponding methyl ether with methyl iodide, silver oxide, and potassium hydroxide.Acid-catalysed solvolysis of the acetates 1 and 2 results in the substitution of the acetate moiety by other nucleophiles and these reactions are not stereospecific.The products of rearomatization of dienyl acetates, dienols and dienyl methyl ethers depend on the acidity and ionizing power of the solvents and are readily explained in terms of reactions involving a nitrocyclohexadienyl cation or acetoxy- (hydroxy-, methoxy-)cyclohexadienyl cation as key intermediates.In the 4-acetoxy-4-alkylcyclohexadienyl cation 1,2-migration of the acetoxyl group is more rapid then alkyl migration, but 1,2-alkyl migration is faster then migration of the hydroxyl or methoxyl groups in the corresponding cations. 1-Ethyl-4-methoxy-4-methylcyclohexa-2,5-dien-1-ol and 4-ethyl-3-nitrotoluene are significant minor products in the solvolysis of 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dien-1-ol in aqueous methanol.Nitration of p-ethyltoluene in the presence of sulfuric acid or in trifluoracetic anhydride gives a mixture of 4-ethyl-2-nitro- and 4-ethyl-3-nitrotoluene in a 2:1 ratio.
- Fischer, Alfred,Henderson, George N.
-
p. 2314 - 2327
(2007/10/02)
-