- Synthesis of Multisubstituted Allenes via Palladium-Catalyzed Cross-Coupling Reaction of Propargyl Acetates with an Organoaluminum Reagent
-
We describe a convenient method for the synthesis of multisubstituted allenes from cross-coupling of propargyl acetates with -organoaluminum reagent: The reaction of propargyl acetates with 1.2 equivalents of organoaluminum reagent mediated by Pd(PPh3)2Cl2 (1 mol%)/Ph3P (2 mol%) and K2CO3 in THF may produce tri- or tetrasubstituted allenes in good to excellent yields (83-94%) and high regio-selectivities (up to 99%) at 60 °C in 3-4 hours.
- Zhang, Zhen,Mo, Song,Zhang, Gang,Shao, Xuebei,Li, Qinghan,Zhong, Ying
-
-
Read Online
- Dual Palladium/Copper-Catalyzed anti-Selective Intermolecular Allenylsilylation of Terminal Alkynes: Entry to (E)-Silyl Enallenes
-
A palladium-/copper-cocatalyzed three-component trans-allenylsilylation of terminal alkynes with propargyl acetates and PhMe2SiBpin is described, which is driven by the regioselective allenylation of the alkyne with propargyl acetates and then silylation. This method allows the simultaneous incorporation of an allene and silicon across the CC bond and provides a highly chemo-, regio-, and stereoselective alkyne difunctionalization route to the synthesis of valuable (E)-silyl enallenes. The utility of this method is highlighted by late-stage derivatization of bioactive compounds.
- Yang, Liang-Feng,Wang, Qiu-An,Li, Jin-Heng
-
p. 6553 - 6557
(2021/09/02)
-
- Synthesis and evaluation of 1,1,7,7-tetramethyl-9-azajulolidine (TMAJ) as a highly active derivative of N,N-dimethylaminopyridine
-
1,1,7,7-Tetramethyl-9-azajulolidine (TMAJ), which theoretical studies have suggested as a highly active DMAP analog, was synthesized for the first time. The catalytic activity of TMAJ was confirmed by the acetylation reactions of various tert-alcohols. TMAJ showed much higher catalytic activity than DMAP and one of the highest activity levels among the conventional DMAP analogs. These experimental results were in good agreement with the previous theoretical studies.
- Tsutsumi, Tomohiro,Saitoh, Arisa,Kasai, Tomoyo,Chu, MengYue,Karanjit, Sangita,Nakayama, Atsushi,Namba, Kosuke
-
supporting information
(2020/05/28)
-
- Palladium(II)/Lewis acid cocatalyzed oxidative annulation of 2-alkenylanilines and propargylic esters: An access to benzo[ b]azepines
-
An attractive approach to valuable yet synthetically challenging benzo[b]azepines was established via palladium(II)/Lewis acid cocatalyzed oxidative [5 + 2] annulation of readily available 2-alkenylanilines and propargylic esters. The protocol features mild reaction conditions and good functional group tolerance, constituting an array of benzo[b]azepines in yields of 30-75%.
- Qiao, Hong,Zhang, Shengjun,Li, Kangkang,Cao, Zhengqiang,Zeng, Fanlong
-
p. 10843 - 10851
(2019/09/12)
-
- Palladium-catalyzed, ligand-free SN2’ substitution reactions of organoaluminum with propargyl acetates for the synthesis of multi-substituted allenes
-
We describe a convenient method for the synthesis of multi-substituted allenes from SN2′ substitution reactions organoaluminum with propargyl acetates: The SN2′ substitution reaction of organoaluminum (0.4 mmol) with propargyl acetat
- Shao, Xuebei,Wen, Chang,Zhang, Gang,Cao, Kangping,Wu, Ling,Li, Qinghan
-
-
- Synthesis of multi-substituted allenes from organoalane reagents and propargyl esters by using a nickel catalyst
-
A highly efficient and simple route for the synthesis of multi-substituted allenes has been developed by a nickel catalyzed SN2′ substitution reaction of propargyl esters with organic aluminium reagents under mild conditions, which gave the corresponding multi-substituted allenes in good to excellent yields (up to 92%) and high selectivities (up to 99%) at 60 °C for 6 h in THF. Aryls bearing electron-donating or electron-withdrawing groups in propargyl esters gave products in good yields. In addition, the multi-substituted allenes bearing a thienyl or a pyridyl group were obtained in 95-97% selectivities with isolated yields of 72-83%. Furthermore, the SN2′ substitution reaction worked efficiently with propargyl carbonate compounds as well. On the basis of the experimental results, a possible catalytic cycle has been proposed.
- Shao, Xue Bei,Zhang, Zhen,Li, Qing Han,Zhao, Zhi Gang
-
p. 4797 - 4806
(2018/07/13)
-
- Highly Efficient Synthesis of Multi-Substituted Allenes from Propargyl Acetates and Organoaluminum Reagents Mediated by Palladium
-
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.
- Zhang, Zhen,Shao, Xuebei,Zhang, Gang,Li, Qinghan,Li, Xinying
-
p. 3643 - 3653
(2017/08/16)
-
- Asymmetric Intermolecular Heck Reaction of Propargylic Acetates and Cycloalkenes to Access Fused Cyclobutenes
-
An asymmetric Heck annulation of propargylic acetates with several types of cyclic olefins affords highly strained cyclobutenes in high enantioselectivity.
- Jiao, Zhiwei,Shi, Qi,Zhou, Jianrong Steve
-
p. 14567 - 14571
(2017/10/23)
-
- Photoredox-catalyzed oxytrifluoromethylation of allenes: Stereoselective synthesis of 2-trifluoromethylated allyl acetates
-
We have developed novel oxytrifluoromethylation of aryl-substituted allenes by photoredox catalysis. The present photocatalytic system allows direct and stereoselective synthesis of 2-CF3-allyl acetates bearing tetrasubstituted CF3-a
- Tomita, Ren,Koike, Takashi,Akita, Munetaka
-
supporting information
p. 4681 - 4684
(2017/07/10)
-
- Templated carbene metathesis reactions from the modular assembly of enol-diazo compounds and propargyl acetates
-
A Lewis acid mediated coupling reaction of enol-diazo nucleophiles and propargyl acetates has provided rapid and diverse access to complex alkynyl-tethered diazocarbonyl compounds. The ability of the coupling reaction to vary critical functionality flanking the diazo group was explored as a way to direct the outcome of a series of metal-catalyzed carbene metathesis cascade reactions. These cascade reactions provided diverse, biologically interesting carbocyclic and heterocyclic compounds in only a few steps from readily available materials. A general coupling strategy for the formation of alkynyl-substituted diazocarbonyl templates for catalytic cascade reactions is described. With the synthetic flexibility imparted to the coupling process and the facile cyclization of the first-formed metal carbene to secondary vinyl carbene templates, selective ylide, C-H insertion, and atom-transfer processes provide directed functionalization in cyclic compounds.
- Qian, Yu,Shanahan, Charles S.,Doyle, Michael P.
-
supporting information
p. 6032 - 6037
(2013/09/24)
-
- C-C bond formation with carbon dioxide promoted by a silver catalyst
-
A catalytic amount of silver benzoate with 7-methyl-1,5,7-triazabicyclo[4. 4.0]dec-5-ene (MTBD) was an effective catalytic system for the reaction of carbon dioxide with various ketones containing an alkyne group at an appropriate position (see scheme). These reactions afforded the corresponding γ-lactone derivatives in good to high yields under mild conditions. Copyright
- Kikuchi, Satoshi,Sekine, Kohei,Ishida, Tomonobu,Yamada, Tohru
-
supporting information; scheme or table
p. 6989 - 6992
(2012/09/25)
-