128773-72-8Relevant articles and documents
An easily assembled highly active ruthenium initiator for olefin metathesis
Buschmann, Nicole,Wakamatsu, Hideaki,Blechert, Siegfried
, p. 667 - 670 (2004)
A practical and easily assembled synthesis of new ruthenium alkylidene precatalyst 8 is described, which exhibits excellent metathesis activity in ring-closing and ring-opening cross metathesis processes.
Bifunctional Iminophosphorane-Catalyzed Enantioselective Sulfa-Michael Addition to Unactivated α,β-Unsaturated Amides
Dixon, Darren J.,Formica, Michele,Hamlin, Trevor A.,Rozsar, Daniel,Yamazaki, Ken
, p. 1006 - 1015 (2022/02/03)
The first metal-free catalytic intermolecular enantioselective Michael addition to unactivated α,β-unsaturated amides is described. Consistently high enantiomeric excesses and yields were obtained over a wide range of alkyl thiol pronucleophiles and elect
A General Iridium-Catalyzed Reductive Dienamine Synthesis Allows a Five-Step Synthesis of Catharanthine via the Elusive Dehydrosecodine
Almehmadi, Yaseen A.,Dixon, Darren J.,Gabriel, Pablo,Wong, Zeng Rong
supporting information, p. 10828 - 10835 (2021/07/31)
A new reductive strategy for the stereo- and regioselective synthesis of functionalized isoquinuclidines has been developed. Pivoting on the chemoselective iridium(I)-catalyzed reductive activation of β,γ-unsaturated δ-lactams, the efficiently produced reactive dienamine intermediates readily undergo [4 + 2] cycloaddition reactions with a wide range of dienophiles, resulting in the formation of bridged bicyclic amine products. This new synthetic approach was extended to aliphatic starting materials, resulting in the efficient formation of cyclohexenamine products, and readily applied as the key step in the shortest (five-step) total synthesis of vinca alkaloid catharanthine to date, proceeding via its elusive biosynthetic precursor, dehydrosecodine.
Transition-Metal-Free Multiple Functionalization of Piperidines to 4-Substituted and 3,4-Disubstituted 2-Piperidinones
Chamorro-Arenas, Delfino,Nolasco-Hernández, Alejandro A.,Fuentes, Lilia,Quintero, Leticia,Sartillo-Piscil, Fernando
supporting information, p. 4671 - 4676 (2020/03/10)
Remote and multiple functionalization of piperidines without the use of transition-metal catalysts and elaborate directing groups is one of the major challenges in organic synthesis. Herein is reported an unprecedented two-step protocol that enables the multiple functionalization of piperidines to either 4-substituted or trans-3,4-disubstituted 2-piperidones. First, by exploiting the duality of TEMPO reactivity, which under oxidative and thermal conditions fluctuates between cationic and persistent-radical form, a novel multiple C(sp3)-H oxidation of piperidines to α,β-unsaturated 2-piperidones was developed. Second, the intrinsic low reactivity of the unsaturated piperidones toward conjugated Grignard additions was overcome by using trimethylsilyl chloride (TMSCl) as Lewis acid. Subsequently, conjugated Grignard addition/electrophilic trapping protocol provided substituted 2-piperidone intermediates, some of which were then transformed into pharmaceutical alkaloids.
Preparation of aα,β-Unsaturated Lactams through intramolecular electrophilic carbamoylation of Alkenes
Yasui, Yoshizumi,Kakinokihara, Issei,Takeda, Hiroshi,Takemoto, Yoshiji
experimental part, p. 3989 - 3993 (2010/03/24)
A general, synthetic method for the preparation of α, βunsaturated lactams startingsei from alkenylchloroformamides has been developed. The reaction was complete within five minutes at 150 °C in N-methylpyrrolidone with a catalytic amount of HBr under mic
Metathesis catalysts
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Page/Page column 8-9, (2008/12/06)
The invention relates to polymeric transition metal catalysts, to processes for preparing them, to intermediates and also to the use of the transition metal catalysts as catalysts in organic reactions, in particular in olefin metathesis reactions.
One-pot dehydrogenation of carboxylic acid derivatives to α,β-unsaturated carbonyl compounds under mild conditions
Matsuo, Jun-Ichi,Aizawa, Yayoi
, p. 407 - 410 (2007/10/03)
Carboxylic acid derivatives such as N-acyl-2-oxazolidones, δ-lactones, and δ-lactams were smoothly dehydrogenated to the corresponding α,β-unsaturated carbonyl compounds in one-pot manner at -78°C just by treating their lithium enolates with N-tert- butyl
Novel ruthenium-based metathesis catalysts containing electron-withdrawing ligands: Synthesis, immobilization, and reactivity
Halbach, Tobias S.,Mix, Stefan,Fischer, Dirk,Maechling, Simon,Krause, Jens O.,Sievers, Carsten,Blechert, Siegfried,Nuyken, Oskar,Buchmeiser, Michael R.
, p. 4687 - 4694 (2007/10/03)
The syntheses and reactivity of seven different ruthenium-based metathesis catalysts are described. Ru(CF3COO)2(PCy 3)(=CH-2-(2-PrO)C6H4) (1),Ru(CF 3COO)2(1,3-dimesityldihydroimi
Unprecedented copper-catalyzed asymmetric conjugate addition of organometallic reagents to α,β-unsaturated lactams
Pineschi, Mauro,Moro, Federica Del,Gini, Francesca,Minnaard, Adriaan J.,Feringa, Ben L.
, p. 1244 - 1246 (2007/10/03)
For the first time, an excellent enantioselectivity has been obtained in the conjugate addition of hard organometallic reagents to α,β-unsaturated lactams bearing appropriate protecting-activating groups on the nitrogen.
A self-generating, highly active, and recyclable olefin-metathesis catalyst
Connon, Stephen J.,Dunne, Aideen M.,Blechert, Siegfried
, p. 3835 - 3838 (2007/10/03)
Sequential ring-opening-metathesis polymerization and cross-metathesis reactions allow a one-pot synthesis of the illustrated ruthenium catalyst. This conceptually novel polymer-bound catalyst shows excellent metathesis activity and recyclability.
