67838-03-3Relevant academic research and scientific papers
Radical Aryl Migration from Boron to Carbon
Daniliuc, Constantin G.,Mück-Lichtenfeld, Christian,Studer, Armido,Wang, Dinghai
supporting information, p. 9320 - 9326 (2021/07/19)
Radical aryl migration reactions represent a unique type of organic transformations that involve the intramolecular migration of an aryl group from a carbon or heteroatom to a C- or heteroatom-centered radical through a spirocyclic intermediate. Various elements, including N, O, Si, P, S, Sn, Ge, and Se, have been reported to participate in radical aryl migrations. However, radical aryl migration from a boron center has not been reported to date. In this communication, radical 1,5-aryl migration from boron to carbon in aryl boronate complexes is presented. C-radicals readily generated through radical addition onto alkenyl aryl boronate complexes are shown to engage in 1,5-aryl migration reactions to provide 4-aryl-alkylboronic esters. As boronate complexes can be generatedin situby the reaction of alkenylboronic acid esters with aryl lithium reagents, the aryl moiety is readily varied, providing access to a series of arylated products starting from the same alkenylboronic acid ester via divergent chemistry. Reactions proceed with high diastereoselectivity under mild conditions, and also the analogous 1,4-aryl shifts are feasible. The suggested mechanism is supported by DFT calculations.
Rhodium-Catalyzed Cyclization of O,ω-Unsaturated Alkoxyamines: Formation of Oxygen-Containing Heterocycles
Escudero, Julien,Bellosta, Véronique,Cossy, Janine
supporting information, p. 574 - 578 (2018/02/21)
O,ω-Unsaturated N-tosyl alkoxyamines undergo unexpected RhIII-catalyzed intramolecular cyclization by oxyamination to produce oxygen-containing heterocycles. Mechanistic studies show that an aziridine intermediate seems to be responsible for the formation of the heterocycles, possibly via a RhV species.
Gold(i)-catalyzed dehydrogenative cycloisomerization of 1,5-enynes
Chen, Gen-Qiang,Fang, Wei,Wei, Yin,Tang, Xiang-Ying,Shi, Min
, p. 10799 - 10802 (2016/09/07)
The gold(i)-catalyzed dehydrogenative cycloisomerization of cyclopropane-tethered 1,5-enynes proceeded smoothly to give multisubstituted benzene derivatives in good to excellent yields. Synthetically important benzocyclobutenes can be produced in high yields in the presence of a gold(i) catalyst and DDQ. Furthermore, this reaction also works very well for non-cyclopropane tethered 1,5-enynes.
Synthesis of β,β-disubstituted γ-butyrolactones by chemo-selective oxidation of 1,4-diols and γ-hydroxy olefins with rucl3/NaIO4
Gao, Rong,Fan, Rong,Canney, Daniel J.
supporting information, p. 661 - 665 (2015/03/14)
Substituted γ-butyrolactones represent an important group of structural fragments commonly found in natural products, receptor ligands, and drug molecules. Interest in preparing a library of substituted γ-butyrolactones and finding that limited routes to β-substituted lactones exist, led to the development of an efficient approach for the synthesis of β,β-disubstituted γ-butyrolactones. Readily prepared substituted 1,4-diols and γ-hydroxy olefins were treated with the -RuCl3/NaIO4 oxidation system to provide the target β,β-disubstituted γ-butyrolactones in modest to good yields. The reaction goes through a lactol intermediate that was isolated and characterized for selected compounds. The approach supplies an efficient and versatile method for the synthesis of these important heterocyclic structures. Importantly, the present work is the first report that demonstrates the ability of RuCl3/NaIO4 to selectively oxidize primary hydroxyl groups in the presence of secondary alcohols to prepare lactones in good yields.
Intramolecular Hydroalkoxylation of Unactivated Alkenes Using Silane-Iodine Catalytic System
Fujita, Shoji,Abe, Masanori,Shibuya, Masatoshi,Yamamoto, Yoshihiko
supporting information, p. 3822 - 3825 (2015/08/18)
A novel catalytic system using I2 and PhSiH3 for the intramolecular hydroalkoxylation of unactivated alkenes is described. NMR study indicated that in situ generated PhSiH2I is a possible active catalytic species. This catalytic system allows an efficient intramolecular hydroalkoxylation of phenyl-, trialkyl-, and 1,1-dialkyl-substituted alkenes as well as a variety of unactivated monoalkyl- and 1,2-dialkyl-substituted alkenes at room temperature. Mechanistic consideration based on significant experimental observations is also discussed.
Copper(I)-catalyzed borylative exo -cyclization of alkenyl halides containing unactivated double bond
Kubota, Koji,Yamamoto, Eiji,Ito, Hajime
supporting information, p. 2635 - 2640 (2013/03/29)
A borylative exo-cyclization of alkenyl halides has been reported. The reaction includes the regioselective addition of a borylcopper(I) intermediate to unactivated terminal alkenes, followed by the intramolecular substitution of the resulting alkylcopper(I) moiety for the halide leaving groups. Experimental and theoretical investigations of the reaction mechanism have also been described. This reaction provides a new method for the synthesis of alkylboronates containing strained cycloalkyl structures from simple starting materials.
Copper-catalysed intramolecular O-H addition to unactivated alkenes
Adrio, Luis A.,Quek, Louisa Shuyi,Taylor, Jason G.,Kuok (Mimi) Hii, King
supporting information; experimental part, p. 10334 - 10338 (2010/02/28)
Intramolecular cyclisation of ω-alkenoic acids and alkenols can be achieved using a catalytic amount of Cu(OTf)2 to afford lactones and cyclic ethers, offering a practical alternative to existing catalysts.
One-pot regio- and stereoselective cyclization of 1,2,n-triols
Zheng, Tao,Narayan, Radha S.,Schomaker, Jennifer M.,Borhan, Babak
, p. 6946 - 6947 (2007/10/03)
A simple and efficient process to cyclize triols containing a 1,2-diol functionality with a pendant hydroxyl group is presented. The one-pot procedure converts the 1,2-diol into an ortho ester in situ, which upon treatment with a Lewis acid generates a cyclic acetoxonium intermediate. This intermediate is subsequently trapped by the pendant hydroxyl group to generate a cyclic ether. The stereochemistry of the 1,2-diol is transferred to the product with complete fidelity (inversion at the site of cyclization), and the reaction proceeds with high regioselectivity. The process is akin to the Lewis acid-catalyzed intramolecular ring-opening of epoxides with hydroxyl groups yielding cyclic ethers of various sizes with regio- and stereochemical control. Copyright
NOVEL 4-(2FUROYL)AMINOPIPERIDINES, INTERMEDIATES IN SYNTHESIZING THE SAME,PROCESS FOR PRODUCING THE SAME AND MEDICINAL USE OF THE SAME
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Page 40, (2008/06/13)
There are provided novel 4-(2-furoyl)aminopiperidines represented by the general formula (I), their synthetic intermediates, processes for their preparation and medicaments containing them. In the above formula, X is CH or N, and Y is a group of the following general formula (II), formula (II-a) or formula (III): wherein a, b and c are each an integer of 0-6; Z is CH2 or NH; W is O or S; T is O or N-R15 wherein R15 is H, a C1-C6 alkyl group, a benzyl group or a phenethyl group; and R1 is H, a C1-C6 alkoxycarbonyl group, a benzyloxycarbonyl group, or the like.The 4-(2-furoyl) aminopiperidine derivatives according to this invention possess opioid μ antagonistic activity and are useful for the treatment or prevention of side effects which are caused by μ receptors agonist and which are selected from constipation, nausea/emesis or itch, or for the treatment or prevention of idiopathic constipation, postoperative ileus, paralytic ileus, irritable bowel syndrome or chronic pruritus.
Composes heterocycliques spiranniques. V. Synthese et etude configurationnelle dans la serie de l'oxa-2 spirodecane
Picard, Philippe,Moulines, Jean,Lecoustre, Max
, p. 65 - 70 (2007/10/02)
The 8-t-butyl-2-oxaspirodecan-3-one, 8-t-butyl-2-oxaspirodecane and its 3-methylated derivatives were synthesized by different routes starting from methyl 4-t-butylcyclohexanecarboxylate, 4-t-butylmethylenecyclohexane and methyl 4-t-butylcyclohexylidenecyanoacetate.The cis (-CH2O axial) and trans (-CH2O equatorial) isomers were isolated by preparative HPLC ; their configurations were established from (1) the known stereoselectivity of the reaction involved in the cis/trans ratio controlling step (2) their proton and 13C nmr spectra.
