3482-63-1Relevant academic research and scientific papers
Highly Discriminative and Chemoselective Deprotection/Transformations of Acetals with the Combination of Trialkylsilyl Triflate/2,4,6-Collidine
Ohta, Reiya,Matsumoto, Nao,Ueyama, Yoshifumi,Kuboki, Yuichi,Aoyama, Hiroshi,Murai, Kenichi,Arisawa, Mitsuhiro,Maegawa, Tomohiro,Fujioka, Hiromichi
, p. 6432 - 6443 (2018/05/30)
Acetals are the most useful protecting groups for carbonyl functional groups. In addition to the role of protection, they can also be used as synthons of carbonyl functions. Previously, we developed a chemoselective deprotection and nucleophilic substitution of acetals from aldehydes in the presence of ketals. This article describes the highly discriminative and chemoselective transformations of acetals bearing different substitution patterns, different types of acetals, as well as mixed acetals. These reactions can achieve the transformations that cannot be attained by conventional methods, and their results strongly suggest the combination of R3SiOTf/2,4,6-collidine to promote such unprecedented phenomena.
Platinum-catalyzed nucleophilic addition of vinylsilanes at the β-position
Miura, Katsukiyo,Inoue, Gen,Sasagawa, Hisashi,Kinoshita, Hidenori,Ichikawa, Junji,Hosomi, Akira
supporting information; experimental part, p. 5066 - 5069 (2009/12/28)
In the presence of catalytic amounts of PtCl2 and metal Iodides, β-substituted vlnylsllanes reacted with aldehydes at the β-position to give allyl silyl ethers. The Pt-catalyzed addition to aromatic aldehydes proceeded efficiently in the presence of Lil. The combined use of PtCl 2 and Mnl2 was found to be effective In addition to aliphatic aldehydes.
A triruthenium carbonyl cluster bearing a bridging acenaphthylene ligand: An efficient catalyst for reduction of esters, carboxylic acids, and amides by trialkylsilanes
Matsubara, Kouki,Iura, Takafumi,Maki, Tomoyuki,Nagashima, Hideo
, p. 4985 - 4988 (2007/10/03)
An efficient reduction of carboxylic acids, esters, and amides with trialkylsilanes is accomplished using a triruthenium carbonyl cluster bearing a bridging acenaphthylene ligand, (μ3,η2:η3:η5 -acenaphthylene)Ru3(CO)7, as the catalyst. Preactivation of the catalyst by hydrosilanes accelerates the reactions. Sterically small trialkylsilanes are effective in these reactions. Reduction of carboxylic acids and amides efficiently produces the corresponding silyl ethers and amines, respectively. Reduction of esters gives a mixture of silyl and alkyl ethers, but can be controlled by changing the silanes and solvents.
TRIMETHYLSILYLDIAZOMETHANE: A CONVENIENT REAGENT FOR THE O-METHYLATION OF ALCOHOLS
Aoyama, Toyohiko,Shioiri, Takayuki
, p. 5507 - 5508 (2007/10/02)
Trimethylsilyldiazomethane smoothly reacts with alcohols in dichloromethane in the presence of 42percent aqueous fluoroboric acid to give methyl ethers in good to high yields.
A Novel Method for the Preparation of Ethers from Carbonyl Compounds with Benzenetellurol Catalyzed by ZnI2
Nagakawa, Keiichi,Osuka, Masahiro,Sasaki, Kazuaki,Aso, Yoshio,Otsubo, Tetsuo,Ogura, Fumio
, p. 1331 - 1334 (2007/10/02)
Benzenetellurol is shown to behave as an effective reagent for the reductive conversion of carbonyl compounds into unsymmetrical ethers under the catalytic influence of ZnI2.
Oxidation of Alkyl Phenyl Selenides, Tellurides, and Telluroxides with meta-Chloroperbenzoic Acid for a Facile and Novel Transformation of C-Se and C-Te Bonds to C-O Bonds
Uemura, Sakae,Fukuzawa, Shin-ichi
, p. 471 - 480 (2007/10/02)
In sharp contrast to the well-known selenoxide elimination leading to olefins, the treatment of alkyl phenyl selenides (PhSeR) with an excess of meta-chloroperbenzoic acid (MCPBA; 2-5 equiv. to a selenide) in alcohol at room temperature affords the corresponding dialkyl ethers by the substitution of a phenylselenium (PhSe) moiety with an alkoxy group.A similar reaction proceeds by using alkyl phenyl tellurides (PhTeR) and telluroxides , a facile substitution of PhTe or PhTe(O) moiety by an alkoxy group being observed.Methanol is the most appropriate solvent for these oxidations and alkyl methyl ethers are formed in excellent yields.The reaction is accompanied by phenyl migration when applied to some selenides, tellurides, and telluroxides having a phenyl group at a vicinal position to the PhSe, PhTe, or PhTe(O) moiety.Application to the methoxyselenation and methoxytelluration products of cyclohexene and cycloheptene results in a ring-contraction to afford the dimethyl acetals of cyclopentane- and cyclohexane-carbaldehyde, respectively.In case of an allylic phenyl selenide, a sigmatropic rearrangement giving a rearranged allylic alcohol occurs in much preference to the substitution by the methoxy group.Other oxidizing agents than MCPBA such as NaIO4, H2O2, t-BuOOH, and ozone are generally ineffective under similar conditions.It is proposed that the reaction mainly takes place as follows.Alkyl phenyl selenone, alkyl phenyl tellurone, or the MCPBA addition product to them is formed as a reactive intermediate in which an alkyl C-Se or alkyl C-Te bond fission occurs heterolytically by a nucleophilic attack of alcohol, sometimes accompanied by a 1,2-shift of the β-substituent, i.e., phenyl migration and ring-contraction.
NOVEL OXIDATION OF ALKYL PHENYL TELLURIDES AND TELLUROXIDES WITH meta-CHLOROPERBENZOIC ACID: REPLACEMENT OF TELLURIUM MOIETY BY METHOXY GROUP ACCOMPAINED BY RING CONTRACTION AND PHENYL MIGRATION
Uemura, Sakae,Fukuzawa, Shin-ichi
, p. 4347 - 4350 (2007/10/02)
Oxidation of alkyl phenyl tellurides and telluroxides with meta-chloroperbenzoic acid in methanol at room temperature afforded the corresponding alkyl methyl ethers in high yields.The reaction was accompained by phenyl migration and ring-contraction respectively when applied to the compounds having phenyl group next to the tellurium moiety and to the methoxytelluration products of cyclic olefins.
A Novel, Simple Method for Transformation of C-Se to C-O Bonds
Uemura, Sakae,Fukuzawa, Shin-ichi,Toshimitsu, Akio
, p. 1501 - 1502 (2007/10/02)
Oxidation of alkyl phenyl selenides with m-chloroperbenzoic acid in methanol at room temperature affords the corresponding alkyl methyl ethers almost quantitatively, the reaction being accompanied by phenyl migration and ring-contraction respectively when applied to selenides having a phenyl group vicinal to the phenylselenium moiety and to some methoxyselenation products of cyclic olefins.
