91639-39-3Relevant academic research and scientific papers
Ammonium-directed olefinic epoxidation: Kinetic and mechanistic insights
Brennan, Meabh B.,Claridge, Timothy D.W.,Compton, Richard G.,Davies, Stephen G.,Fletcher, Ai M.,Henstridge, Martin C.,Hewings, David S.,Kurosawa, Wataru,Lee, James A.,Roberts, Paul M.,Schoonen, Anne K.,Thomson, James E.
, p. 7241 - 7261 (2012/11/07)
The ammonium-directed olefinic epoxidations of a range of differentially N-substituted cyclic allylic and homoallylic amines (derived from cyclopentene, cyclohexene, and cycloheptene) have been investigated, and the reaction kinetics have been analyzed. The results of these studies suggest that both the ring size and the identity of the substituents on nitrogen are important in determining both the overall rate and the stereochemical outcome of the epoxidation reaction. In general, secondary amines or tertiary amines with nonsterically demanding substituents on nitrogen are superior to tertiary amines with sterically demanding substituents on nitrogen in their ability to promote the oxidation reaction. Furthermore, in all cases examined, the ability of the (in situ formed) ammonium substituent to direct the stereochemical course of the epoxidation reaction is either comparable or superior to that of the analogous hydroxyl substituent. Much slower rates of ring-opening of the intermediate epoxides are observed in cyclopentene-derived and cycloheptene-derived allylic amines as compared with their cyclohexene-derived allylic and homoallylic amine counterparts, allowing for isolation of these intermediates in both of the former cases.
Stereoselective synthesis of imidazolidin-2-ones via Pd-catalyzed alkene carboamination. Scope and limitations
Fritz, Jonathan A.,Wolfe, John P.
, p. 6838 - 6852 (2008/09/21)
A method for the synthesis of imidazolidin-2-ones from N-allylureas and aryl or alkenyl bromides via Pd-catalyzed carboamination reactions is described. The N-allylurea precursors are prepared in one step from readily available allylic amines and isocyanates, and the Pd-catalyzed reactions effect the formation of a C-C bond, a C-N bond, and up to two stereocenters in a single step. Good diastereoselectivities are obtained for the conversion of substrates bearing allylic substituents to 4,5-disubstituted imidazolidin-2-ones, and excellent selectivity for the generation of products resulting from syn-addition across the alkene is observed when substrates derived from cyclic alkenes or E-1,2-disubstituted alkenes are employed. A brief discussion of reaction mechanism and product stereochemistry is presented.
Synthesis of sultams by intramolecular Heck reaction
Merten, Sandra,Froehlich, Roland,Kataeva, Olga,Metz, Peter
, p. 754 - 758 (2007/10/03)
A novel access to α-methylene-γ-sultams via the intramolecular Heck reaction of α-bromovinylsulfonamides derived from allylic amines is reported. These heterocycles are potent Michael acceptors towards sulfur nucleophiles.
Intramolecular Diels-Alder reaction of cyclenic trienes: Stereoselectivity and NMR structure determination
Blond, Alain,Platzer, Nicole,Guy, Alain,Dhotel, Helene,Serva, Laurence
, p. 283 - 293 (2007/10/03)
A series of trienes possessing an internally cyclenic dienophilic group undergo thermal intramolecular DielsAlder (IMDA) reaction with high selectivity for the cis-fused products. A concentrated solution of LIC1O4 in diethyl ether catalyzes the IMDA reaction of cyclenic nitrotrienes, giving rise to the irans-fused compounds. The stereochcmical outcome of these various processes are rationalized in terms of a minimization of the steric interactions between the ring and the chain on the one hand and the endo-stabilization from the nitro group on the other. The structures of the cycloadducts have been carefully determined by NMR 1H and 13C spectroscopy: dipolar interactions, detected via nuclear Overhauser effects, and criteria based on scalar coupling and moreover on chemical shifts have been employed. Conformational preferences were observed. Elsevier,.
Transition Metal-Catalyzed Radical Cyclizations: A Low-Temperature Process for the Cyclization of N-Protected N-Allyltrichloroacetamides to Trichlorinated γ-Lactams and Application to the Stereoselective Preparation of β,γ-Disubstituted γ-Lactams
Nagashima, Hideo,Ozaki, Nobuyasu,Ishii, Masayuki,Seki, Koji,Washiyama, Masayoshi,Itoh, Kenji
, p. 464 - 470 (2007/10/02)
Cyclisations of N-substituted N-allyltrichloroacetamides, where the substituent is an alkyl, Cbz, Boc, Ts, or Ms group, are catalyzed by a 1:1 mixture of CuCl and bipyridine to give the corresponding β,γ-trichlorinated γ-lactams in high yields.The reactions proceed at temperatures from -78 deg C to room temperature.Cyclizations of N-allyltrichloroacetamides of acyclic secondary allylic amines are achieved with good selectivity; the cis/trans ratios of the γ-lactams formed were dependent on the substituents on the nitrogen atom.The stereochemical outcome is compared with that of free-radical cyclization.
