3400-78-0Relevant academic research and scientific papers
Preparation of Optically Active (4aα,8aβ)-Octahydro-4a-methyl-8-methylene-2(1H)-naphthalenone, a Key Intermediate for the Enantioselective Synthesis of Eudesmane Sesquiterpenes
Utaka, Masanori,Fujii, Yasuyuki,Takeda, Akira
, p. 1103 - 1104 (1986)
The titled optically active methylene ketone was prepared in 45percent ee from 3-methyl-1,2-cyclohexanedione by use of a novel asymmetric Michael addition with (R,R)-(-)-2,3-butanediol as chiral auxiliary.
Practical preparation of diosphenols by ring opening of α,β-epoxyketones catalyzed by silica gel supported acids
Zhu, Rui,Xing, Lixin,Wang, Xinyan,Cheng, Chuanjie,Liu, Bo,Hu, Yuefei
, p. 2267 - 2271 (2008/02/09)
The mixed acid (H2SO4-HOAc) catalyzed ring opening of α,β-epoxyketone was the most used method for the preparation of diosphenols, but it seriously suffered from poor yields and tedious workup operations. By using silica gel supported mixed acid (H2SO 4-HOAc), a variety of α,β-epoxyketones were converted into the corresponding diosphenols in unprecedented high yields within a few minutes. Georg Thieme Verlag Stuttgart.
Samarium diiodide-promoted intramolecular ketone-ester coupling reaction: Novel cyclization and ring expansion pathway
Iwaya, Kazuki,Nakamura, Momoe,Hasegawa, Eietsu
, p. 5067 - 5070 (2007/10/03)
When ethyl 2-substituted-1-indanone-2-carboxylates were treated with samarium diiodide (SmI2), ring expansion products such as 3-substituted-1,2-naphthoquinones were isolated. Alcohols were also obtained as the mixture of cis- and trans-isomers of hydroxy and ester substituents. A reaction mechanism involving intramolecular addition of samarium ketyl radicals to ester substituents followed by ring expansion was proposed for the formation of the one-carbon homologated products. Similarly, reaction of ethyl 1-substituted-2-oxo-1-cyclopentanecarboxylates with SmI2 produced 3-substituted-2-hydroxy-2-cyclohexenones along with the corresponding alcohols.
Conversion of α,β-epoxyketones to diosphenols using 6-methyl-2-pyridone anion as an hydroxide equivalent
Ponaras,Meah
, p. 9031 - 9035 (2007/10/03)
Treatment of α,β-epoxyketones with 6-methyl-2-pyridone anion gives diosphenol (6-methyl-2-pyridyl) ethers that can be cleaved to diosphenols under mild basic conditions. (C) 2000 Elsevier Science Ltd.
A tandem Horner-Emmons olefination-gonjugate addition approach to the synthesis of 1,5-Disubstituted-6-azabicyclo[3.2.1]octanes based on the AE ring structure of the norditerpenoid alkaloid methyllycaconitine
Callis, David J.,Thomas, Noel F.,Pearson, David P. J.,Potter, Barry V. L.
, p. 4634 - 4640 (2007/10/03)
A novel Horner-Emmons olefination conjugate addition reaction of N-acetylamides to form 1,5-disubstituted-6-azabicyclo[3.2.1]octanes with two bridgehead quarternary carbon centers is reported. This reaction is a key step in an approach to the synthesis of small ring analogues based on the AE ring structure of the Delphinium norditerpenoid, methyllycaconitine (MLA) (1). Initially, 3-(hydroxymethyl)cyclohex-2-en-1-one (10) was selected as the starting material to these structures, but its generation proved inefficient. In contrast, the synthesis of 3-[(phenylthio)methyl]cyclohex-2-en-1-one (6) and 3-(1,3-dithian-2-yl)cyclohex-2-en-1-one (11) proceeded in good yield. Subsequent hydrocyanation, ketalization, reduction, acetylation, deprotection of the acetal, and Horner-Emmons olefination-conjugate addition reaction to form 1-[(phenylthio)methyl]-5-[(ethoxycarbonyl)methyl]-6-acetamido-6-azabicyclo[3.2. 1]octane(28), 1-(1,3-dithian-2-yl)-5-[(ethoxycarbonyl)methyl]-6-acetyl-6-azabicyclo[3.2.1] octane (29), respectively, are reported, as well as for readily available 3-methylcyclohex-2-en-1-one (12). Studies on the Pummerer rearrangement of 28 and subsequent desulfurization and reduction to form an hydroxymethyl-substituted azabicyclo[3.2.1.]octane (40) and then selective protection to form a protected hydroxyethyl N-ethyl (hydroxymethyl)azabicyclo-[3.2.1]octane (3) are also described.
Conjugate addition of lithium diorganocuprate reagents to the enol tosylate of a 1,2-diketone
Charonnat,Mitchell,Keogh
, p. 315 - 318 (2007/10/02)
The conjugate addition of lithium diorganocuprate reagents to the enol tosylate of 1,2-cyclohexanedione has been investigated. The intermediate enolates eliminate para-toluenesulfinate ion to generate the alkylated 1,2-dicarbonyl system.
A New Synthesis of 3-Alkyl-1,2-cyclohexanediones from 2-Alkylcyclohexanones Using Iodine/Copper(II) Acetate
Horiuchi, C. Akira,Kiyomiya, Hiroshi,Takahashi, Masaaki,Suzuki, Yasuto
, p. 785 - 786 (2007/10/02)
The reactions of 2-alkyl-, 2,5-dimethyl-, and 3,3,5-trimethylcyclohexanone with iodine/copper(II) acetate in boiling aqueous acetic acid gave the respective 3-alkyl-, 3,6-dimethyl-, and 3,5,5-trimethyl-1,2-cyclohexanediones in 40-70percent yields.This new
Reactions of Diethoxytriphenylphosphorane with Diastereoisomeric 3-Methylcyclohexane-1,2-diols. Control of Regioselectivity by Methyl Substitution during Cyclodehydration and Rearrangement of 1,2-Diols
Robinson, Philip L.,Evans, Slayton A.
, p. 3860 - 3863 (2007/10/02)
The diastereoisomeric 3-methylcyclohexane-trans-1,2-diols undergo cyclodehydration with diethoxytriphenylphosphorane (DTPP) to afford the cis- and trans-3-methylcyclohexene oxides.The ratio of cis and trans epoxides is best explained by assuming preferential phosphoranylation of the C1 hydroxyl group followed by " 3-exo-tet " alkoxide displacement of triphenylphosphine oxide.The diastereoisomers of 3-methylcyclohexane-cis-1,2-diol afford stable ? -dioxyphosphoranes when allowed to react with DTPP.These 1,3,2-dioxaphosphoranes were subjected to flash thermolysis ( 300 deg C ) conditions and afforded the isomeric 2- and 3-methylcyclohexanones via a 1,2-hydride shift.
CONVENIENT PREPARATION OF 1,2-CYCLOHEXANEDIONES
Utaka, Masanori,Matsushita, Seishiro,Takeda, Akira
, p. 779 - 780 (2007/10/02)
1,2-Cyclohexanedione and 3-alkyl-1,2-cyclohexanediones were prepared in good to excellent yields from the corresponding 2,6-dibromocyclohexanones by treatment with aqueous NaOH.
