2699-87-8Relevant academic research and scientific papers
Highly efficient reagents for Br/Mg exchange
Krasovskiy, Arkady,Straub, Bernd F.,Knochel, Paul
, p. 159 - 162 (2006)
(Chemical Equation Presented) The conversion of electron-rich aryl bromides into the corresponding Grignard compounds proceeds within 2 h at 25°C in the presence of 0.55 equivalents of the new reagent sBu2Mg· LiCl. The high reactivity of magnes
Electrophilic Trifluoromethylthiolation/Semipinacol Rearrangement: Preparation of β-SCF3 Carbonyl Compounds with α-Quaternary Carbon Center
Xi, Chao-Chao,Chen, Zhi-Min,Zhang, Shu-Yu,Tu, Yong-Qiang
supporting information, p. 4227 - 4230 (2018/07/29)
A new and modular electrophilic trifluoromethylthiolation/semipinacol rearrangement of allylic silyl ethers has been developed under mild conditions. This approach allows the formation of a number of β-SCF3 carbonyl compounds with a cyclic and all-carbon quaternary center framework in moderate to good yields. It should be noted that this achievement is a metal-free process and just requires the use of simple acetyl chloride as an acidic promoter. Additionally, an interesting H-migration in competition with aryl-migration process was revealed.
α-Quaternary Mannich Bases through Copper-Catalyzed Amination-Induced 1,2-Rearrangement of Allylic Alcohols
Weng, Wei-Zhi,Sun, Jian-Guo,Li, Ping,Zhang, Bo
supporting information, p. 9752 - 9755 (2017/07/25)
A novel copper-catalyzed amination-induced 1,2-rearrangement reaction of allylic alcohols has been developed under simple and mild conditions. The commercially available N-fluorobenzenesulfonimide (NFSI) is employed as an amination reagent. In this transformation, not only alkyl, but also aryl substituents can efficiently undergo 1,2-carbon atom migration, thereby providing an efficient and powerful route to prepare a wide range of α-quaternary Mannich bases. The reaction features a broad substrate scope, operational simplicity, and excellent practicality.
A Ligand-Free Pt3Cluster Catalyzes the Markovnikov Hydrosilylation of Alkynes with up to 106Turnover Frequencies
Rivero-Crespo, Miguel A.,Leyva-Pérez, Antonio,Corma, Avelino
, p. 1702 - 1708 (2017/02/10)
The Pt-catalyzed hydrosilylation of alkynes is the procedure of choice to obtain vinylsilanes, and is claimed to be the most relevant application of Pt in organic synthesis. More than half a century after its discovery, only β-vinylsilanes (anti-Markovnikov addition) are obtained with simple Pt catalysts, whereas α-vinylsilanes (Markovnikov addition) remain elusive compounds. Here the catalysis of the Markovnikov hydrosilylation of terminal alkynes by Pt3clusters, in parts-per-million amounts, to give a wide variety of α-vinylsilanes in reasonable isolated yields and with turnover frequencies that can reach up to one million per hour is reported. Moreover, these α-vinylsilanes are reactive in well-stablished C?C bond-forming cascade reactions, in which the corresponding β-isomers are unreactive. Besides its efficiency and synthetic usefulness, this catalytic system is an excellent example of how the atom-by-atom aggregation of a catalytic metal leads to a different selectivity for a given reaction.
Synthesis of functionalized epoxides by copper-catalyzed alkylative epoxidation of allylic alcohols with alkyl nitriles
Bunescu, Ala,Wang, Qian,Zhu, Jieping
supporting information, p. 1890 - 1893 (2015/04/27)
A copper-catalyzed oxyalkylation of allylic alcohols using nonactivated alkyl nitriles as reaction partners was developed. A sequence involving generation of an alkyl nitrile radical followed by its addition to a double bond and a copper-mediated formation of C(sp3)-O bond was proposed to account for the reaction outcome. The protocol provided an efficient route to functionalized tri- and tetrasubstituted epoxides via formation of a C(sp3)-C(sp3) and a C(sp3)-O bond with moderate to excellent diastereoselectivity.
C2-symmetric cyclic selenium-catalyzed enantioselective bromoaminocyclization
Chen, Feng,Tan, Chong Kiat,Yeung, Ying-Yeung
supporting information, p. 1232 - 1235 (2013/03/28)
A catalytic asymmetric bromocyclization of trisubstituted olefinic amides that uses a C2-symmetric mannitol-derived cyclic selenium catalyst and a stoichiometric amount of N-bromophthalimide is reported. The resulting enantioenriched pyrrolidine products, which contain two stereogenic centers, can undergo rearrangement to yield 2,3-disubstituted piperidines with excellent diastereoselectivity and enantiospecificity.
One-pot synthesis of α,β-epoxy ketones by palladium-catalyzed epoxidation-oxidation of terminal allylic alcohols
Singh, Fateh V.,Pena, Jesus M.,Stefani, Hélio A.
experimental part, p. 1671 - 1673 (2010/05/19)
Described herein is a one-pot synthesis of α,β-epoxy ketones using a palladium-catalyzed epoxidation-oxidation sequence. Functionalized terminal allylic alcohols are treated with m-CPBA under mild reaction conditions to obtain the α,β-epoxy ketones. The m
α-oxygen-atom induced methylenation of ketones by CH2(ZnI)2
Ukai,Arioka,Yoshino,Fushimi,Oshima,Utimoto,Matsubara
, p. 513 - 514 (2007/10/03)
Ketones bearing a hetero-atom at α-position were methylenated selectively by CH2(ZnI)2 to give allylic alcohols; a nucleophilic attack of the zinc species was accelerated with a coordination of a hetero-atom at α-position.
Novel Conversion of Epoxides to One Carbon Homologated Allylic Alcohols by Dimethylsulfonium Methylide
Alcaraz, L.,Harnett, J. J.,Mioskowski, C.,Martel, J. P.,Gall, T. Le,et al.
, p. 5449 - 5452 (2007/10/02)
The reaction of excess of dimethylsulfonium methylide with terminal, allylic, or benzylic epoxides affords good to excellent yields of one carbon homologated allylic alcohols.
Organomolybdenum and Organotungsten Reagents, III. Selective, Nonbasic Carbonylmethylenation Reagents from MoOCl3(THF)2 and MoOCl4: Formation, Thermolability, Structure
Kauffmann, Thomas,Fiegenbaum, Petra,Papenberg, Michael,Wieschollek, Raphael,Wingbermuehle, Dorothea
, p. 79 - 88 (2007/10/02)
From the family of more than 20 carbonylolefinating μ-methylene molybdenum and tungsten complexes the reagent "3", obtained in solution by treatment of MoOCl3(THF)2 with two equivalents of methyllithium, is probably the most favorable one for chemoselective carbonylolefination reactions.As judged by the 13C- and 1H-NMR spectra the reagent is not a single species, but a mixture of either isomeric 1,3-dioxo-1,3-dimolybda(V)cyclobutane complexes 3, differing in the position of the ligands Cl, O, and THF at the molybdenum atoms, or of oligomers of 3. - Treatment of MoOCl4 with two equivalents of methyllithium gave a carbonylolefinating reagent "4" which, according to NMR data, consists of isomeric or oligomeric 1,3-dioxo-1,3-dimolybda(VI)cyclobutane complexes 4.Both reagents are labile at room temperature, but differ from the classical carbonylolefinating reagents by an acidic rather than a basic character, resistance to hydroxy groups, and high selectivity. Key Words: Carbonylolefination / μ-Methylene complexes / Molybdenum reagent
