934-85-0Relevant articles and documents
Nickel-Catalyzed Directed C6-Selective C-H Alkylation of 2-Pyridones with Dienes and Activated Alkenes
Miura, Wataru,Hirano, Koji,Miura, Masahiro
, p. 5337 - 5344 (2017)
A pyridine-directed, C6-selective nickel-catalyzed ring-contracting C-H alkylation of 2-pyridones with 1,5-cyclooctadiene (cod) has been developed. The reaction proceeds smoothly under external-ligand-free conditions and is accelerated uniquely by a K3PO4 base. Preliminary mechanistic investigations with deuterium-labeled substrates and related reactions with some alkenes are also disclosed.
Polymerization of Allenes by Using an Iron(II) β-Diketiminate Pre-Catalyst to Generate High Mn Polymers
Durand, Derek J.,Webster, Ruth L.,Woof, Callum R.
supporting information, p. 12335 - 12340 (2021/07/19)
Herein, we report an iron(II)-catalyzed polymerization of arylallenes. This reaction proceeds rapidly at room temperature in the presence of a hydride co-catalyst to generate polymers of weight up to Mn=189 000 Da. We have determined the polymer structure and chain length for a range of monomers through a combination of NMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) analysis. Mechanistically, we postulate that the co-catalyst does not react to form an iron(II) hydride in situ, but instead the chain growth is proceeding via a reactive Fe(III) species. We have also performed kinetic and isotopic experiments to further our understanding. The formation of a highly unusual 1,3-substituted cyclobutane side-product is also investigated.
The Catalytic Asymmetric Intermolecular Prins Reaction
Diáz-Oviedo, C. David,Maji, Rajat,List, Benjamin
supporting information, p. 20598 - 20604 (2021/12/14)
Despite their significant potential, catalytic asymmetric reactions of olefins with formaldehyde are rare and metal-free approaches have not been previously disclosed. Here we describe an enantioselective intermolecular Prins reaction of styrenes and paraformaldehyde to form 1,3-dioxanes, using confined imino-imidodiphosphate (iIDP) Br?nsted acid catalysts. Isotope labeling experiments and computations suggest a concerted, highly asynchronous addition of an acid-activated formaldehyde oligomer to the olefin. The enantioenriched 1,3-dioxanes can be transformed into the corresponding optically active 1,3-diols, which are valuable synthetic building blocks.
Asymmetric Markovnikov Hydroaminocarbonylation of Alkenes Enabled by Palladium-Monodentate Phosphoramidite Catalysis
Yao, Ya-Hong,Yang, Hui-Yi,Chen, Ming,Wu, Fei,Xu, Xing-Xing,Guan, Zheng-Hui
supporting information, p. 85 - 91 (2021/01/12)
A palladium-catalyzed asymmetric Markovnikov hydroaminocarbonylation of alkenes with anilines has been developed for the atom-economical synthesis of 2-substituted propanamides bearing an α-stereocenter. A novel phosphoramidite ligand L16 was discovered which exhibited very high reactivity and selectivity in the reaction. This asymmetric Markovnikov hydroaminocarbonylation employs readily available starting materials and tolerates a wide range of functional groups, thus providing a facile and straightforward method for the regio- and enantioselective synthesis of 2-substituted propanamides under ambient conditions. Mechanistic studies revealed that the reaction proceeds through a palladium hydride pathway.
Phosphonium Phenolate Zwitterion vs Phosphonium Ylide: Synthesis, Characterization and Reactivity Study of a Trimethylphosphonium Phenolate Zwitterion
Xiao, Jing,Li, Qiang,Shen, Ruwei,Shimada, Shigeru,Han, Li-Biao
supporting information, p. 5715 - 5720 (2019/11/22)
4-Methoxy-3-(trimethylphosphonio)phenolate was obtained from a regioselective addition of PMe3 to p-quinone monoacetal. This compound undergoes hydrogen isotope exchange with D2O or CD3CN, and is capable of catalyzing H/D exchange of CD3CN with substrates bearing weakly acidic hydrogens. It exhibits similar reactivity to phosphorus ylides for olefinations of aldehydes. A possible tautomerization between the phosphonium phenolate zwitterion and phosphonium ylide is proposed for the first time to rationalize the unique reactivity.
Copper-catalyzed dehydrogenative borylation of terminal alkynes with pinacolborane
Romero, Erik A.,Jazzar, Rodolphe,Bertrand, Guy
, p. 165 - 168 (2016/12/30)
LCuOTf complexes [L = cyclic (alkyl)(amino)carbenes (CAACs) or N-heterocyclic carbenes (NHCs)] selectively promote the dehydrogenative borylation of C(sp)-H bonds at room temperature. It is shown that σ,π-bis(copper) acetylide and copper hydride complexes are the key catalytic species.
Mechanistic insights into catalytic linear cross-dimerization between conjugated dienes and styrenes by a ruthenium(0) complex
Hirano, Masafumi,Ueda, Takao,Komine, Nobuyuki,Komiya, Sanshiro,Nakamura, Saki,Deguchi, Hikaru,Kawauchi, Susumu
, p. 174 - 184 (2015/09/22)
The mechanistic studies for linear cross-dimerization between 2,3-dimethylbuta-1,3-diene and styrene by a Ru(0) complex, Ru(η6-naphthalene)(η4-1,5-COD) (1), are performed both by kinetic and computational studies. This reaction is ba
Taming living carbocations in catalytic direct conjugate addition of simple alkenes to α,Enones
Lv, Jian,Zhong, Xingren,Luo, Sanzhong
supporting information, p. 8293 - 8296 (2014/07/08)
A Lewis acid in the presence of an anionic phosphate ligand enables the addition of alkenes to α,enones. The ligand facilitates selective proton elimination by suppressing competing pathways, thus leading to vinylation adducts in high yields (up to 99%) for a broad range of substrates.
Hydride-rhodium(III)-N-heterocyclic carbene catalysts for vinyl-selective h/d exchange: A structure-activity study
Di Giuseppe, Andrea,Castarlenas, Ricardo,Perez-Torrente, Jesus J.,Lahoz, Fernando J.,Oro, Luis A.
, p. 8391 - 8403 (2014/07/08)
A series of neutral and cationic RhIII-hydride and Rh III-ethyl complexes bearing a NHC ligand has been synthesized and evaluated as catalyst precursors for H/D exchange of styrene using CD 3OD as a deuterium source. Various ligands have been examined in order to understand how the stereoelectronic properties can modulate the catalytic activity. Most of these complexes proved to be very active and selective in the vinylic H/D exchange, without deuteration at the aromatic positions, displaying very high selectivity toward the positions. In particular, the cationic complex [RhClH(CH3CN)3(IPr)]CF 3SO3 showed excellent catalytic activity, reaching the maximum attainable degree of vinylic deuteration in only 20 min. By modulation of the catalyst structure, we obtained improved α/β selectivity. Thus, the catalyst [RhClH(κ2-O,N-C9H 6NO)(SIPr)], bearing an 8-quinolinolate ligand and a bulky and strongly electron-donating SIPr as the NHC, showed total selectivity for the β-vinylic positions. This systematic study has shown that increased electron density and steric demand at the metal center can improve both the catalytic activity and selectivity. Complexes bearing ligands with very high steric hindrance, however, proved to be inactive.
Oxidative cleavage and rearrangement of aryl epoxides using iodosylbenzene: On criegee's trail
Havare, Nizam,Plattner, Dietmar A.
, p. 2036 - 2042 (2013/01/15)
Aryl epoxides undergo rearrangement and oxidative cleavage when reacted with in situ prepared hydroxy-λ3-iodane complexes. The presence of H2O plays a decisive role in steering the reaction path. A mechanistic scheme is proposed that accounts for the observed chemoselectivities. Copyright
