27975-79-7Relevant academic research and scientific papers
Chemoselective Hydroboration of Propargylic Alcohols and Amines Using a Manganese(II) Catalyst
Brzozowska, Aleksandra,Zubar, Viktoriia,Ganardi, Ruth-Christine,Rueping, Magnus
supporting information, p. 3765 - 3769 (2020/04/15)
The first manganese-catalyzed hydroboration of propargylic alcohols and amines as well as internal alkynes is reported. High regio- and stereoselectivity is achieved by applying 2 mol % of a manganese precatalyst based on the readily accessible bis(imino)pyridine ligand and MnCl2 as metal source. Propargylic alcohols and amines, as well as symmetric internal alkynes, were efficiently converted into the corresponding functionalized alkenes, which can serve as important and valuable intermediates for further synthetic applications such as cross-coupling reactions.
Asymmetric Propargylic Radical Cyanation Enabled by Dual Organophotoredox and Copper Catalysis
Lu, Fu-Dong,Liu, Dan,Zhu, Lei,Lu, Liang-Qiu,Yang, Qian,Zhou, Quan-Quan,Wei, Yi,Lan, Yu,Xiao, Wen-Jing
supporting information, p. 6167 - 6172 (2019/04/17)
The first asymmetric propargylic radical cyanation was realized through a dual photoredox and copper catalysis. An organic photocatalyst serves to both generate propargyl radicals and oxidize Cu(I) species to Cu(II) species. A chiral Cu complex functions as an efficient organometallic catalyst to resemble the propargyl radical and cyanide in an enantio-controlled manner. Thus, a diverse range of optically active propargyl cyanides were produced with high reaction efficiency and enantioselectivities (28 examples, 57-97% yields and 83-98% ee). Moreover, mechanistic investigations including experiments and density functional theory calculations were performed to illustrate on the reaction pathway and stereochemical results.
Neighboring Carbonyl Group Assisted Hydration of Unsymmetrical Aryl Alkynes Overriding Regular Selectivity
Mendhekar, Kishor L.,Pradhan, Tapas R.,Mallampudi, N. Arjunreddy,Mohapatra, Debendra K.
, p. 5787 - 5797 (2019/08/21)
A mild and highly regioselective gold-catalyzed hydration of γ-acetoxy aryl alkynes leading to anti-Markovnikov products by the assistance of a neighboring carbonyl group is presented. The reaction procedure operates under room temperature conditions with
Oxidative coupling of tetraalkynyltin with aldehydes leading to alkynyl ketones
Levashov, Andrey S.,Aksenov, Nicolai A.,Aksenova, Inna V.,Konshin, Valeriy V.
, p. 8297 - 8304 (2017/08/14)
The reaction of tetraalkynyltin with aldehydes was studied for the first time. The reaction was shown to proceed as a tandem process of nucleophilic addition of tin acetylide to aldehyde followed by Oppenauer-type oxidation of produced tin alcoholates, an
Highly Efficient Synthesis of Multi-Substituted Allenes from Propargyl Acetates and Organoaluminum Reagents Mediated by Palladium
Zhang, Zhen,Shao, Xuebei,Zhang, Gang,Li, Qinghan,Li, Xinying
, p. 3643 - 3653 (2017/08/16)
A simple and mild catalytic S N 2′ substitution reaction of propargyl acetates with organoaluminum reagents is reported. The S N 2′ substitution reaction of propargyl acetates with organoaluminum reagents mediated by Pd(PhP 3) 2 Cl 2 (1 mol%)/PPh 3 (2 mol%)/K 2 CO 3 in tetrahydrofuran at 60 °C for 3-4 hours afforded the corresponding multi-substituted allenes in good yields (up to 94%) with high selectivities (up to 99%). The process was simple and easily performed, which offers an efficient method to synthesize the multi-substituted allene derivatives.
Enantioselective Alkynylation of Aromatic Aldehydes Catalyzed by a Sterically Highly Demanding Chiral-at-Rhodium Lewis Acid
Luo, Shipeng,Zhang, Xiao,Zheng, Yu,Harms, Klaus,Zhang, Lilu,Meggers, Eric
, p. 8995 - 9005 (2017/09/11)
The enantioselective catalytic alkynylation of aromatic aldehydes is reported using a sterically highly hindered bis-cyclometalated rhodium-based Lewis acid catalyst featuring the octahedral metal as the only stereogenic center. Yields of 58-98% with 79-9
Synthesis of Polysubstituted γ-Butenolides via a Radical Pathway: Cyclization of α-Bromo Aluminium Acetals and Comparison with the Cyclization of α-Bromoesters at High Temperature
Bénéteau, Romain,Despiau, Carole F.,Rouaud, Jean-Christophe,Boussonnière, Anne,Silvestre, Virginie,Lebreton, Jacques,Dénès, Fabrice
supporting information, p. 11378 - 11386 (2015/08/03)
Polysubstituted butenolides were obtained in good to high yields from α-bromoesters derived from propargyl alcohols by a one-pot reaction involving the radical cyclization of α-bromo aluminium acetals, followed by the oxidation of the resulting cyclic aluminium acetals in an Oppenauer-type process and migration of the exocyclic C-C bond into the α,β-position. Comparison with the direct cyclization of α-bromoesters at high temperature and under high dilution conditions is described. Deuterium-labelling experiments allowed us to uncover "invisible" 1,5-hydrogen atom transfers (1,5-HATs) that occur during these cyclization processes, together with the consequences of the latter in the epimerization of stereogenic centres. Compared to the classical approach, the cyclization of aluminium acetals proved to be highly chemoselective and its efficiency was illustrated by the short total syntheses of optically enriched γ-butenolides isolated from Plagiomnium undulatum and from Kyrtuhrix maculans.
Catalytic stereospecific allyl-allyl cross-coupling of internal allyl electrophiles with allylB(pin)
Le, Hai,Batten, Amanda,Morken, James P.
supporting information, p. 2096 - 2099 (2014/05/06)
Application of internal electrophiles in catalytic stereospecific allyl-allyl cross-coupling enable the rapid construction of multisubstituted 1,5-dienes, including those with all carbon quaternary centers. Compounds with minimal steric differentiation ca
Utilization of whole cell mediated deracemization in a chemoenzymatic synthesis of enantiomerically enriched polycyclic chromeno[4,3-b] pyrrolidines
Saravanan, Thangavelu,Jana, Sushital,Chadha, Anju
supporting information, p. 4682 - 4690 (2014/06/24)
Various aryl and alkyl substituted optically pure propargyl alcohols were obtained with excellent ee (up to >99%) and isolated yields (up to 87%) by deracemization using whole cells of Candida parapsilosis ATCC 7330. The whole cells show substrate specificity towards alkyl substituted propargyl alcohols and a switch in the enantioselectivity has been observed from 'R' to 'S' upon increasing the chain length. For the first time, enantiopure (R)-4-(3-hydroxybut-1-ynyl)benzonitrile, (R)-4-(biphenyl-4-yl)but-3-yn-2-ol, (S)-ethyl 3-hydroxy-5-phenylpent-4-ynoate and (S)-4-phenylbut-3-yne-1,2-diol were obtained using this strategy. Optically pure propargyl alcohol thus obtained was used as a chiral starting material in the synthesis of enantiomerically enriched poly-substituted pyrrolidines and a pyrrole derivative successfully demonstrating a chemoenzymatic route. This journal is
Gold(I)-catalyzed bis-alkynylation reaction of aromatic aldehydes with alkynylsilanes
Rubial, Belen,Ballesteros, Alfredo,Gonzalez, Jose M.
, p. 3337 - 3343 (2013/12/04)
The first successful gold(I)-catalyzed reaction of aryl aldehydes with trimethyl(arylethynyl)silanes to furnish bis-alkynylated derivatives is reported. Key C-C bond-forming events involved in the catalytic cycle are analyzed. Copyright
