- Controlled Reduction of Nitriles by Sodium Hydride and Zinc Chloride
-
A new protocol for the controlled reduction of nitriles to aldehydes was developed using a combination of sodium hydride and zinc chloride. The iminyl zinc intermediates derived from aromatic nitriles could be further functionalized with allylmetal nucleophiles to afford homoallylamines. As the method allows the reduction of various aliphatic and aromatic nitriles with a concise procedure under milder reaction conditions and exhibits wide functional group compatibility, it is well suited for use in various opportunities in chemical synthesis.
- Chiba, Shunsuke,Ong, Derek Yiren
-
p. 1369 - 1378
(2020/04/27)
-
- Mild Iridium-Catalysed Isomerization of Epoxides. Computational Insights and Application to the Synthesis of β-Alkyl Amines
-
The isomerization of epoxides to aldehydes using the readily available Crabtree's reagent is described. The aldehydes were transformed into synthetically useful amines by a one-pot reductive amination using pyrrolidine as imine-formation catalyst. The reactions worked with low catalyst loadings in very mild conditions. The procedure is operationally simple and tolerates a wide range of functional groups. A DFT study of its mechanism is presented showing that the isomerization takes place via an iridium hydride mechanism with a low energy barrier, in agreement with the mild reaction conditions. (Figure presented.).
- Cabré, Albert,Cabezas-Giménez, Juanjo,Sciortino, Giuseppe,Ujaque, Gregori,Verdaguer, Xavier,Lledós, Agustí,Riera, Antoni
-
p. 3624 - 3631
(2019/07/10)
-
- Iterative Synthesis of Pluripotent Thioethers through Controlled Redox Fluctuation of Sulfur
-
Target- and diversity-oriented syntheses are based on diverse building blocks, whose preparation requires discrete design and constructive alignment of different chemistries. To enable future automation of the synthesis of small molecules, we have devised a unified strategy that serves the divergent synthesis of unrelated scaffolds such as carbonyls, olefins, organometallics, halides, and boronic esters. It is based on iterations of a nonelectrophilic Pummerer-type C-C coupling enabled by turbo -organomagnesium amides that we have recently reported. The pluripotency of sulfur allows the central building blocks to be obtained by regulating C-C bond formation through control of its redox state.
- Colas, Kilian,Mendoza, Abraham
-
p. 1329 - 1333
(2018/06/13)
-
- Intermolecular Pummerer Coupling with Carbon Nucleophiles in Non-Electrophilic Media
-
A new Pummerer-type C?C coupling protocol is introduced based on turbo-organomagnesium amides, which unlike traditional Pummerer reactions, does not require strong electrophilic activators, engages a broad range of C(sp3)-, C(sp2)-, and C(sp)-nucleophiles, and seamlessly integrates with C?H and C?X magnesiation. Given the central character of sulfur compounds in organic chemistry, this protocol allows access to unrelated carbonyls, olefins, organometallics, halides, and boronic esters through a single strategy.
- Colas, Kilian,Martín-Montero, Raúl,Mendoza, Abraham
-
supporting information
p. 16042 - 16046
(2017/11/21)
-
- Enantioselective Rhodium-Catalyzed Allylic Alkylation of Prochiral α,α-Disubstituted Aldehyde Enolates for the Construction of Acyclic Quaternary Stereogenic Centers
-
A highly enantioselective rhodium-catalyzed allylic alkylation of prochiral α,α-disubstituted aldehyde enolates with allyl benzoate is described. This protocol provides a novel approach for the synthesis of acyclic quaternary carbon stereogenic centers and it represents the first example of the direct enantioselective alkylation of an aldehyde enolate per se. The versatility of the α-quaternary aldehyde products is demonstrated through their conversion to a variety of useful motifs applicable to target-directed synthesis. Finally, mechanistic studies indicate that high levels of asymmetric induction are achieved from a mixture of prochiral (E)- and (Z)-enolates, which provides an exciting development for this type of transformation.
- Wright, Timothy B.,Evans, P. Andrew
-
p. 15303 - 15306
(2016/12/09)
-
- An air-stable cationic iridium hydride as a highly active and general catalyst for the isomerization of terminal epoxides
-
We describe the use of an air-stable iridium hydride catalyst for the isomerization of terminal epoxides into aldehydes with perfect regioselectivity. The system operates at low loadings of catalyst (0.5 mol%), is highly practical, scalable, and tolerates functional groups that would not be compatible with Lewis acids typically used in stoichiometric amounts. Evidence for a rare hydride mechanism are provided. This journal is the Partner Organisations 2014.
- Humbert, Nicolas,Vyas, Devendra J.,Besnard, Céline,Mazet, Clément
-
supporting information
p. 10592 - 10595
(2014/10/15)
-
- Isomerization of terminal epoxides by a [Pd-H] catalyst: A combined experimental and theoretical mechanistic study
-
An unusual palladium hydride complex has been shown to be a competent catalyst in the isomerization of a variety of terminal and internal epoxides. The reaction displayed broad scope and synthetic utility. Experimental and theoretical evidence are provided for an unprecedented hydride mechanism characterized by two distinct enantio-determining steps. These results hold promise for the development of an enantioselective variant of the reaction.
- Vyas, Devendra J.,Larionov, Evgeny,Besnard, Celine,Guenee, Laure,Mazet, Clement
-
supporting information
p. 6177 - 6183
(2013/06/04)
-
- Complementary catalytic strategies to access α-chiral aldehydes
-
The present article summarizes the development of two novel and complementary catalytic methods to access α-chiral aldehydes. A C1-symmetric chiral (P,N) ligand with a structure derived from the ubiquitous binepine scaffold has been specifically designed for the Pd-catalyzed α arylation of aldehydes to access indane derivatives with a well-defined quaternary stereocenter in high yields and excellent enantioselectivities. In addition, a dinuclear palladium hydride catalyst has been synthesized for the isomerization of terminal and trisubstituted epoxides into aldehydes and ketones respectively. Combined experimental and theoretical investigations pointed to an unprecedented 'epoxide-opening/hydride-transfer' sequence. The mechanism also features two distinct enantio-determining steps in the kinetic resolution of racemic epoxides. Schweizerische Chemische Gesellschaft.
- Mazet, Clement
-
p. 658 - 662
(2013/11/06)
-
- SUBSTITUTED POLYCYCLIC CARBAMOYL PYRIDONE DERIVATIVE PRODRUG
-
The present invention provides a compound having antiviral effects, particularly having growth inhibitory activity on influenza viruses, a preferred example of the compound being a substituted 3-hydroxy-4-pyridone derivative prodrug having cap-dependent endonuclease inhibitory activity.
- -
-
Paragraph 2298; 2299; 2300
(2013/08/14)
-
- Oxidative cleavage of α-aryl aldehydes using iodosylbenzene
-
We found that α-aryl aldehydes can be cleaved to chain-shortened carbonyl compounds and formaldehyde by various iodosylbenzene complexes. A mechanistic scheme is presented that accounts for the loss of one carbon atom. Formaldehyde is further oxidized to CO and CO2 under the reaction conditions.
- Havare, Nizam,Plattner, Dietmar A.
-
p. 5078 - 5081,4
(2020/09/15)
-
- Catalytic asymmetric C-H insertions of rhodium(II) azavinyl carbenes
-
A highly efficient enantioselective C-H insertion of azavinyl carbenes into unactivated alkanes has been developed. These transition metal carbenes are directly generated from readily available and stable 1-sulfonyl-1,2,3-triazoles in the presence of chiral Rh(II) carboxylates and are used for C-H functionalization of alkanes to access a variety of β-chiral sulfonamides.
- Chuprakov, Stepan,Malik, Jamal A.,Zibinsky, Mikhail,Fokin, Valery V.
-
supporting information; experimental part
p. 10352 - 10355
(2011/08/05)
-
- Ru-catalyzed asymmetric hydrogenation of racemic aldehydes via dynamic kinetic resolution: Efficient synthesis of optically active primary alcohols
-
A highly efficient asymmetric hydrogenation of racemic α-arylaldehydes via dynamic kinetic resolution has been developed by using [RuCl2(SDPs)(diamine)] complexes as catalysts, providing chiral primary alcohols in excellent enantioselectivities. Copyright
- Xie, Jian-Hua,Zhou, Zhang-Tao,Kong, Wei-Ling,Zhou, Qi-Lin
-
p. 1868 - 1869
(2007/10/03)
-
- Intrazeolite photooxygenation of chiral alkenes. Control of facial selectivity by confinement and cation-π interactions
-
Depending on the nature of the substituents on the stereogenic carbon atom, the ene reaction of singlet oxygen with several chiral alkenes by confinement within thionin-supported zeolite NaY, may exhibit significant changes on facial selectivity by comparison to their photooxygenation reaction in solution. It is proposed that, apart from the conformational consequences as a result of the alkene confinement within the zeolite cavities, a synergism between Na+-π interactions and singlet oxygen-Na+ interactions plays a significant role in the transition states of ene hydroperoxidation. Within NaY, the diastereoselectivity may significantly depend on the site selectivity, as probed through specific deuterium labelling of trisubstituted alkenes bearing a gem-dimethyl group. In certain cases, a remote stereogenic centre relative to the reacting double bond may induce enhanced diastereoselection and regioselectivity.
- Stratakis, Manolis,Raptis, Christos,Sofikiti, Nikoletta,Tsangarakis, Constantinos,Kosmas, Giannis,Zaravinos, Ioannis-Panagiotis,Kalaitzakis, Dimitris,Stavroulakis, Dimitris,Baskakis, Constantinos,Stathoulopoulou, Aggeliki
-
p. 10623 - 10632
(2007/10/03)
-
- Remarkable Change of the Diastereoselection in the Dye-Sensitized Ene Hydroperoxidation of Chiral Alkenes by Zeolite Confinement
-
(Equation presented) The ene reaction of singlet oxygen with chiral trisubstituted alkenes bearing an alkyl and a phenyl group at the stereogenic center is erythro diastereoselective in solution and threo diastereoselective if carried out within zeolite Na-Y. The change of the diastereoselection trend by zeolite confinement is attributed to a synergism of steric effects and cation-π interactions.
- Stratakis, Manolis,Kalaitzakis, Dimitris,Stavroulakis, Dimitris,Kosmas, Giannis,Tsangarakis, Constantinos
-
p. 3471 - 3474
(2007/10/03)
-