1590-08-5Relevant articles and documents
Amine-catalyzed decarboxylative aldol reaction of β-ketocarboxylic acids with trifluoropyruvates
Kawanishi, Ryouta,Hattori, Shinya,Iwasa, Seiji,Shibatomi, Kazutaka
, (2019)
Decarboxylative aldol reaction of aliphatic carboxylic acids is a useful method for C–C bond formation because carboxylic acids are an easily available class of compounds. In this study, we found that the decarboxylative aldol reaction of tertiary β-ketocarboxylic acids and trifluoropyruvates proceeded smoothly to yield the corresponding aldol products in high yields and with high diastereoselectivity in the presence of a tertiary amine catalyst. In this reaction, we efficiently constructed a quaternary carbon center and an adjacent trifluoromethylated carbon center. This protocol was also extended to an enantioselective reaction with a chiral amine catalyst, and the desired product was obtained with up to 73% enantioselectivity.
Probing the regioselective C-deuteriation of lithium enolates derived from 2-methyl-tetralone in the presence of substituted tertiary amines
Begum, Mothia,Chavda, Sameer,Coumbarides, Gregory S.,Dingan, Marco,Eames, Jason,Suggate, Michael J.,Weerasooriya, Neluka
, p. 707 - 732 (2006)
Results are reported on the regioselective C-deuteriation of 2-methyl-tetralone using a series of D-sources and tertiary amines as potential mediators. The results presented further aid the understanding of kinetic deuteriation of both 'base-containing' and 'base-free' enolates. Copyright
A chiral 1,4-oxazin-2-one: Asymmetric synthesis versus resolution, structure, conformation and VCD absolute configuration
Solladie-Cavallo,Sedy,Salisova,Biba,Welch,Nafie,Freedman
, p. 2703 - 2707 (2001)
1,4-Oxazin-2-one 3 is obtained from 2-pinanone in 4 steps and 78% overall yield. Enantiopure (e.e. >99%) (R)-(+)-3 and (S)-(-)-3 were obtained through chiral supercritical fluid chromatography (using a semi preparative Chiralpak AS column) with almost quantitative recovery of material. The structure and the boat-conformation of the lactone ring have been determined by NMR and the absolute configuration determined by VCD.
-
Barry et al.
, p. 4737 (1971)
-
The synthesis and characterization of 2-trideuteriomethyl and 2,2-di(trideuteriomethyl) aryl ketones
Coumbarides, Gregory S.,Eames, Jason,Weerasooriya, Neluka
, p. 935 - 942 (2002)
Results are reported on the synthesis and characterization of a variety of trideuteriomethyl aryl ketones. Copyright
Electron transfer promoted regioselective ring-opening reaction of cyclopropyl silyl ethers
Hasegawa, Eietsu,Yamaguchi, Naoto,Muraoka, Hiroyasu,Tsuchida, Hiroyuki
, p. 2811 - 2814 (2007)
Oxidative ring-opening reactions of cyclopropyl silyl ethers incorporated into bicyclo[m.1.0]alkane framework were investigated. The results show that the regioselectivities for ring-opening of intermediate radical cations, formed by single electron transfer, are governed by the nature of the nucleophile as well as oxidizing species.
Role of the Ring Methyl Groups in 2′,3′-Benzoabscisic Acid Analogues
Wan, Chuan,Hong, Qilin,Zhang, Xueqin,Zeng, Yuejuan,Yang, Dongyan,Che, Chuanliang,Ding, Shanshan,Xiao, Yumei,Li, Jia-Qi,Qin, Zhaohai
, (2019)
Five analogues of iso-PhABA (20) developed earlier by our research group were designed and synthesized. The bioassay results show that the number and position of methyl groups along with the substitution of hydrogen atoms of the methyl group have a great influence on the activity. Compared with iso-PhABA, the inhibitory activity of diMe-PhABA (21) on seed germination and rice seedling growth decreased slightly; however, it significantly reduced the capability of inhibiting wheat embryo germination. Both 3′-deMe-iso-PhABA (22) and 2′-deMe-PhABA (23) exhibited weak inhibitory activities, and 11′-methoxy iso-PhABA (24a/24b) was much more efficient than its isomer 24c/24d in all bioassays. These results reveal the preservation of quaternary carbon at the 2′ or 3′ position is necessary to maintain its ABA-like biological activity, and demethylation at the 3′ position has a more significant effect. The selectivity of these compounds to different physiological processes makes them available as selective probes for different ABA receptors.
(R)-(+)-[VCD(-)984]-4-Ethyl-4-methyloctane: A cryptochiral hydrocarbon with a quaternary chiral center. (1) synthesis of the enantiopure compound and unambiguous determination of absolute configuration
Fujita, Takuma,Obata, Kazuhiro,Kuwahara, Shunsuke,Nakahashi, Atsufumi,Monde, Kenji,Decatur, John,Harada, Nobuyuki
, p. 6372 - 6384 (2010)
Enantiopure (R)-(+)-[VCD(-)984]-4-ethyl-4-methyloctane (1), a cryptochiral hydrocarbon with a quaternary chiral center, was synthesized by the use of 2-methoxy-2-(1-naphthyl)propionate (Mα NP) and (-)-camphorsultam dichlorophthalic (CSDP) acid methods. The diastereomeric Mα NP and CSDP acid esters prepared from racemic 2-butyl-2-methyl-1-tetralols, were effectively separated by HPLC on silica gel, and their absolute configurations were unambiguously determined by X-ray crystallographic analysis and 1H NMR anisotropy methods. The recovered enantiopure 2-butyl-2-methyl-1-tetralol [(1S,2S)-(+)-cis-9] was then converted into the hydrocarbon (+)-1, the R absolute configuration of which was unambiguously determined for the first time. The structure of hydrocarbon 1 was also confirmed by NMR HSQC-TOCSY analysis. Copyright
Enantioselective protonation of a lithium enolate derived from 2-methyl-1-tetralone using chiral sulfonamides
Coumbarides, Gregory S.,Eames, Jason,Scheuermann, J. Erik W.,Sibbons, Kevin F.,Suggate, Michael J.,Watkinson, Michael
, p. 906 - 909 (2005)
The synthesis of enantiomerically enriched (R)-2-methyl-1-tetralone (1) with 77% e.e. was achieved through protonation of its lithium enolate (3) using a C2-symmetric tris-sulfonamide (6) as an internal chiral proton source. Access to the complementary (S)-enantiomer 1 with 33% e.e. was achieved using a related C2-symmetric bis-sulfonamide (9) as the chiral proton source.
Preparation method 2 - methyl -1 - tetrahydronaphthalene
-
Paragraph 0037; 0043-0045, (2021/10/30)
The invention relates to the field of synthesis of tetralin ketone derivatives, and provides a preparation method of 2 - methyl -1 - tetrahydronaphthalene, wherein 1 - tetrahydronaphthalene is subjected to hydrogen extraction by one-pot method. Methylation is carried out by methyl trifluoroacetate, methyl benzene sulfonate or bromomethane, and the conventional methylation reagent iodomethane with large toxicity is replaced, 1 -tetralin -2 - methyl -2 - methyl formate is generated in a one-pot reaction. The hydrobromic acid is reacted with 1 -tetralin -2 - methyl -2 - methyl formate, and in the post-treatment step, the product is collected in a reduced pressure distillation manner, and finally 2 - methyl -1 -tetralin ketone is obtained. The preparation method of 2 - methyl -1 - tetrahydronaphthalene provided by the embodiment of the invention has the advantages of short synthetic route, no need of ultralow temperature reaction, no column chromatography, simple purification, high yield and up 84.3%.
Rhenium(I)-Catalyzed C-Methylation of Ketones, Indoles, and Arylacetonitriles Using Methanol
Shee, Sujan,Kundu, Sabuj
, p. 6943 - 6951 (2021/05/29)
A ReCl(CO)5/MeC(CH2PPh2)3 (L2) system was developed for the C-methylation reactions utilizing methanol and base, following the borrowing hydrogen strategy. Diverse ketones, indoles, and arylacetonitriles underwent mono-and dimethylation selectively up to 99% yield. Remarkably, tandem multiple methylations were also achieved by employing this catalytic system.
α-Methylation of Ketones with Methanol Catalyzed by Ni/SiO2-Al2O3
Charvieux, Aubin,Duguet, Nicolas,Métay, Estelle
supporting information, p. 3694 - 3698 (2019/06/13)
α-Methylation of ketones with methanol catalyzed by a cheap and easy to handle Ni/SiO2-Al2O3 was explored. After optimization of the reaction between propiophenone and methanol, the desired product was obtained in 95 % isolated yield. A wide range of ketones was methylated under the optimized conditions (16 examples). This procedure was extended to a three-component cross-benzylation-methylation of acetophenone.
