14003-84-0Relevant articles and documents
A GENERAL SYNTHESIS OF ISOTWIST-8-EN-2-ONES FROM o-(3-BUTENYL)PHENOLS
Macas, Tadas S.,Yates, Peter
, p. 147 - 150 (1983)
Wessely oxidation of o-(3-butenyl)phenols with lead tetraacetate gives 2,4-cyclohexadienone derivatives that on heating undergo intramolecular Diels-Alder reactions to give 3-acetoxyisotwist-8-en-2-ones.
New stabilising groups for lateral lithiation of ortho-cresol derivatives
Wilkinson, James A.,Raiber, Eun-Ang,Ducki, Sylvie
, p. 6434 - 6436 (2007)
1-(2-Methoxyethoxy)-2-methylbenzene and 1-(2-dimethylaminoethoxy)-2-methylbenzene have been lithiated using sec-BuLi under a variety of conditions and the laterally lithiated species trapped with electrophiles.
Synthesis of Highly Substituted Phenols and Benzenes with Complete Regiochemical Control
Zhang, Xiaojie,Beaudry, Christopher M.
supporting information, p. 6086 - 6090 (2020/08/12)
Substituted phenols are requisite molecules for human health, agriculture, and diverse synthetic materials. We report a chemical synthesis of phenols, including penta-substituted phenols, that accommodates programmable substitution at any position. This method uses a one-step conversion of readily available hydroxypyrone and nitroalkene starting materials to give phenols with complete regiochemical control and in high chemical yield. Additionally, the phenols can be converted into highly and even fully substituted benzenes.
Enantioselective Halo-oxy- and Halo-azacyclizations Induced by Chiral Amidophosphate Catalysts and Halo-Lewis Acids
Lu, Yanhui,Nakatsuji, Hidefumi,Okumura, Yukimasa,Yao, Lu,Ishihara, Kazuaki
supporting information, p. 6039 - 6043 (2018/05/14)
Catalytic enantioselective halocyclization of 2-alkenylphenols and enamides have been achieved through the use of chiral amidophosphate catalysts and halo-Lewis acids. Density functional theory calculations suggested that the Lewis basicity of the catalyst played an important role in the reactivity and enantioselectivity. The resulting chiral halogenated chromans can be transformed to α-Tocopherol, α-Tocotrienol, Daedalin A and Englitazone in short steps. Furthermore, a halogenated product with an unsaturated side chain may provide polycyclic adducts under radical cyclization conditions.
Synthesis of Chiral 1,4-Benzodioxanes and Chromans by Enantioselective Palladium-Catalyzed Alkene Aryloxyarylation Reactions
Hu, Naifu,Li, Ke,Wang, Zheng,Tang, Wenjun
supporting information, p. 5044 - 5048 (2016/04/26)
A highly enantioselective alkene aryloxyarylation led to the high-yielding formation of a series of 1,4-benzodioxanes, 1,4-benzooxazines, and chromans containing quaternary stereocenters with excellent enantioselectivity. The sterically bulky and conformationally well defined chiral monophosphorus ligand L4 or L5 was responsible for the high reactivity and enantioselectivity of these transformations. The application of this method to the synthesis of the chiral chroman backbone of α-tocopherol was demonstrated. One P is plenty: A sterically bulky and conformationally well defined chiral monophosphorus ligand enabled the highly enantioselective synthesis of a series of Oheterocycles containing a quaternary stereocenter by alkene aryloxyarylation (see scheme; X=O, C, N). The application of this transformation to the synthesis of the chiral chroman backbone of α-tocopherol is demonstrated.
Synthetic studies toward polytwistane hydrocarbon nanorods
Olbrich, Martin,Mayer, Peter,Trauner, Dirk
, p. 2042 - 2055 (2015/09/08)
A synthetic strategy toward the intriguing hydrocarbon nanorod polytwistane is outlined. Our approach aims toward the polymerization of acetylene starting from precursors that would provide a helical bias for the formation of polytwistane. Both transition-metal-catalyzed and radical polymerizations were investigated. Two potential initiator molecules were synthesized that could be used for either approach. Although the intended regioselectivities were not observed, unusual organopalladium complexes and numerous compounds with novel carbon skeletons were obtained.
Efficient intramolecular hydroalkoxylation of unactivated alkenols mediated by recyclable lanthanide lriflate ionic liquids: Scope and mechanism
Dzudza, Alma,Marks, Tobin J.
supporting information; experimental part, p. 3403 - 3422 (2010/06/21)
Lanthanide triflate complexes of the type [Ln(OTf)3] (Ln = La, Sm, Nd, Yb, Lu) serve as effective, recyclable catalysts for the rapid intramolecular hydroalkoxylation (HO)/cyclization of primary/secondary and aliphatic/aromatic hydroxyalkenes in imidazolium-based room-temperature ionic liquids (RTILs) to yield the corresponding furan, pyran, spirobicyclic furan, spirobicyclic furan/pyran, benzofuran, and isochroman derivatives. Products are straightforwardly isolated from the catalytic solution, conversions exhibit Markovnikov regioselectivity, and turnover frequencies are as high as 47 h -1 at 120°C. The ring-size rate dependence of the primary alkenol cyclizations is 5>6, consistent with a sterically controlled transition state. The hydroalkoxylation/cyclization rates of terminal alkenols are slightly more rapid than those of internal alkenols, which suggests modest steric demands in the cyclic transition state. Cyclization rates of aryl-functionalized hydroxyalkenes are more rapid than those of the linear alkenols, whereas five- and five/six-membered spirobicyclic skeletons are also regioselectively closed. In cyclization of primary, sterically encumbered alkenols, turnoverfrequency dependence on metal-ionic radius decreases by approximately 80fold on going from La3+ (1.160 A) to Lu3+ (0.977 A), presumably reflecting steric impediments along the reaction coordinate. The overall rate law for alkenol hydroalkoxylation/cyclization is v≈[catalys] 1[alkenol]1. An observed ROH/ROD kinetic isotope effect of 2.48 (9) is suggestive of a catalytic pathway that involves kinetically significant intramolecular proton transfer. The present activation parameters-enthalpy (ΔH≠) = 18.2 (9) Kcal mol-1, entropy (ΔS≠) = -17.0 (1.4) eu, and energy (E,) = 18.2 (8) kcal mol-1-suggest a highly organized transition state. Proton scavenging and coordinative probing results suggest that the lanthanide inflates are not simply precursors of free triflic acid. Based on the kinetic and mechanistic evidence, the proposed catalytic pathway invokes hydroxyl and olefin activation by the electron-deficient Ln3+ center, and intramolecular H+ transfer, followed by alkoxide nucleophilic attack with ring closure.
Palladium catalyzed isomerization of alkenes: A pronounced influence of an o-phenol hydroxyl group
Fan, Jinmin,Wan, Changfeng,Wang, Qiang,Gao, Linfeng,Zheng, Xiaoqi,Wang, Zhiyong
supporting information; experimental part, p. 3168 - 3172 (2011/02/25)
A novel palladium catalyzed isomerization of alkenes has been found, where an ortho-phenol hydroxyl group has a pronounced influence on the isomerization.
New stabilising groups for lateral lithiation of ortho-cresol derivatives and a new route to 2-substituted chromans
Wilkinson, James A.,Raiber, Eun-Ang,Ducki, Sylvie
, p. 6329 - 6333 (2008/12/20)
2-(2-Methoxyethoxy)-toluene and 2-(2-dimethylaminoethoxy)-toluene have been lithiated using sec-BuLi under a variety of conditions and the laterally lithiated species trapped with electrophiles, including but-1-ene oxide, leading to a new synthesis of 2-ethylchroman.
Ground and excited-state intramolecular interactions in phenol-olefin bichromophoric compounds
Bosch-Montalva, M. Teresa,Domingo, Luis R.,Jimenez, M. Consuelo,Miranda, Miguel A.,Tormos, Rosa
, p. 2175 - 2179 (2007/10/03)
The intramolecular OH ... π interactions of the phenolic and olefinic chromophores in o-propenyl and o-butenyl phenols 1a-d in the ground and excited states have been studied by (a) ab initio Hartree-Fock calculations using the 3-21G and 6-31G** basis sets, (b) FTIR spectral measurements in the gas phase, (c) fluorescence emission studies and (d) product studies. Such interactions appear to play a key role in the photochemical behaviour of the four compounds.
