18937-78-5Relevant articles and documents
Palladium-catalyzed electrochemical carbonylation of alkynes under very mild conditions
Chiarotto,Carelli
, p. 881 - 886 (2002)
Terminal alkynes were carbonylated under very mild conditions to yield acetylenecarboxylates under atmospheric pressure of carbon monoxide at room temperature using palladium(II) catalyst in combination with its anodic recycling at a graphite electrodes.
Organocatalytic Trans Semireduction of Primary and Secondary Propiolamides: Substrate Scope and Mechanistic Studies
Grams, R. Justin,Lawal, Monsurat M.,Szwetkowski, Connor,Foster, Daniel,Rosenblum, Carol Ann,Slebodnick, Carla,Welborn, Valerie Vaissier,Santos, Webster L.
supporting information, p. 172 - 178 (2021/10/14)
We report a chemoselective, phosphine-catalyzed semireduction of primary and secondary propiolamides. In the presence of stoichiometric pinacolborane and catalytic n-tributylphosphine, a variety of propiolamides were successfully converted to the corresponding acrylamides in excellent yield with (E)-stereoselectivity. The reaction condition is tolerant of various functional groups including alkene, alkyne, ketone, or ester. Deuterium labeling studies established that the hydride from activated pinacolborane is added to the α-carbon and the proton on the amide nitrogen is abstracted by the ?-carbon to furnish the (E)-acrylamides. DFT calculations revealed a clear energetic driving force for the (E)- over the (Z)-isomer. (Figure presented.).
Organocatalytic trans Phosphinoboration of Internal Alkynes
Fritzemeier, Russell G.,Nekvinda, Jan,Rosenblum, Carol Ann,Santos, Webster L.,Slebodnick, Carla,Vogels, Christopher M.,Westcott, Stephen A.
supporting information, p. 14358 - 14362 (2020/07/04)
We report the first trans phosphinoboration of internal alkynes. With an organophosphine catalyst, alkynoate esters and the phosphinoboronate Ph2P-Bpin are efficiently converted into the corresponding trans-α-phosphino-β-boryl acrylate products in moderate to good yield with high regio- and Z-selectivity. This reaction operates under mild conditions and demonstrates good atom economy, requiring only a modest excess of the phosphinoboronate. X-ray crystallography experiments allowed structural assignment of the unprecedented and densely functionalized (Z)-α-phosphino-β-boryl acrylate products.
N-triflyl-propiolamides: Preparation and transamidation reactions
Fiore, Vito A.,Maas, Gerhard
, p. 3586 - 3595 (2019/05/27)
N-Trifluoromethylsulfonyl-propiolamides have been prepared by two methods: a) N-triflation of secondary acetylenic carboxanilides, prepared in two steps from terminal alkynes, with triflic anhydride (Tf2O) and b) from terminal alkynes and an aryl or alkyl isocyanate followed by Tf2O in a consecutive one-pot reaction. The title compounds are bench-stable and insensitive to water and alcohols but amenable to transamidation reactions with a wide range of amine nucleophiles. Conversely, they are excellent reagents for the propynoylation of ammonia, primary and secondary amines, anilines, and hydrazines.
Triphenylphosphine Oxide-Catalyzed Selective α,β-Reduction of Conjugated Polyunsaturated Ketones
Xia, Xuanshu,Lao, Zhiqi,Toy, Patrick H.
supporting information, p. 1100 - 1104 (2019/05/24)
The scope of the triphenylphosphine oxide-catalyzed reduction of conjugated polyunsaturated ketones using trichlorosilane as the reducing reagent has been examined. In all cases studied, the α,β-C=C double bond was selectively reduced to a C-C single bond while all other reducible functional groups remained unchanged. This reaction was applied to a large variety of conjugated dienones, a trienone, and a tetraenone. Additionally, a tandem one-pot Wittig/conjugate-reduction reaction sequence was developed to produce γ,δ-unsaturated ketones directly from simple building blocks. In these reactions the byproduct of the Wittig reaction served as the catalyst for the reduction reaction. This strategy was then used in the synthesis of naturally occurring moth pheromones to demonstrate its utility in the context of natural-product synthesis.
Oxidative Alkoxycarbonylation of Alkynes by Means of Aryl α-Diimine Palladium(II) Complexes as Catalysts
Beltrani, Michela,Carfagna, Carla,Milani, Barbara,Mancuso, Raffaella,Gabriele, Bartolo,Fini, Francesco
, p. 3244 - 3253 (2016/10/21)
The straightforward in situ synthesized bis(2,6-diisopropyl)acenaphthenequinonediimine palladium triflate catalyst was generally employed for both the mono-alkoxycarbonylation of terminal alkynes, and the bis-alkoxycarbonylation of 1,2-disubstituted alkynes by using mild reaction conditions [carbon monoxide pressure (PCO)=4 bar, temperature=20 °C]. Utilizing low catalyst loading (down to 0.5 mol%), a variety of propiolic esters were synthesized with good to excellent isolated yields. Most importantly the system was very efficient not only with methanol but also with a range of different alcohols, starting from the less hindered benzyl alcohol to the most hindered ones, such as isopropyl alcohol and tert-butyl alcohol. In addition, aromatic and aliphatic 1,2-disubstituted alkynes were converted into maleic acid derivatives, together with an acid-catalyzed isomerization reaction, showing modest to good selectivity and excellent combined yields. In particular 3-hexyne showed a satisfactory degree of selectivity for the maleic diesters of methanol and benzyl alcohol, obtaining the corresponding products with good isolated yields. (Figure presented.).
CuI/Pd0 cooperative dual catalysis: Tunable stereoselective construction of tetra-substituted alkenes
Vercruysse, Sebastien,Cornelissen, Loic,Nahra, Fady,Collard, Laurent,Riant, Olivier
supporting information, p. 1834 - 1838 (2014/03/21)
This paper describes a tunable and stereoselective dual catalytic system that uses copper and palladium reagents. This cooperative silylcupration and palladium-catalyzed allylation readily affords trisubstituted alkenylsilanes. Fine-tuning the reaction conditions allows selective access to one stereoisomer over the other. This new methodology tolerates different substituents on both coupling partners with high levels of stereoselectivity. The one-pot reaction involving a CuI/Pd0 cooperative dual catalyst directly addresses the need to develop more time-efficient and less-wasteful synthetic pathways.
Platinum-catalyzed hydrosilylations of internal alkynes: Harnessing substituent effects to achieve high regioselectivity
Rooke, Douglas A.,Ferreira, Eric M.
supporting information; experimental part, p. 3225 - 3230 (2012/05/31)
Rule of thumb: The high yielding title reaction is described with a focus on understanding the factors that govern the regioselectivity of the process (see scheme). Electronic, steric, and functional group properties all influence the selectivity, an understanding of which allows the selective formation of trisubstituted vinylsilanes, which are synthetically useful compounds for accessing stereodefined alkenes. Copyright
Acid-catalyzed synthesis of bicyclo[3. n.1]alkenediones
Michaelides, Iacovos N.,Darses, Benjamin,Dixon, Darren J.
supporting information; experimental part, p. 664 - 667 (2011/04/24)
An acid-catalyzed Dieckmann-type reaction has been developed to access functionalized bicyclo[3.2.1]alkenediones. This methodology has been successfully extended to more substituted and larger ring homologues, providing a new and efficient route to the core of numerous attractive natural products and their analogues.
Rhodium-catalyzed aryl- and alkylation-oligomerization of alkynoates with organoboron reagents giving salicylates
Yasuhara, Yuichi,Nishimura, Takahiro,Hayashi, Tamio
supporting information; experimental part, p. 2130 - 2132 (2010/08/04)
The reaction of alkynoates with aryl- or alkylboron reagents in the presence of a rhodium/diene catalyst gave high yields of salicylate derivatives with high selectivity, which consist of three or four molecules of the alkynoate and one organic group derived from the organoboron reagents. The Royal Society of Chemistry.
