- Pd catalyzed couplings of “superactive esters” and terminal alkynes: Application to flavones and γ-benzopyranones construction
-
Lewis base, N-methylmorpholine (NMM) accelerated Pd-catalyzed Sonogashira coupling of steric hindered super active esters, 1a–1e, and terminal alkynes. This approach provided an efficient synthetic protocol for a broad array of acylated o-alkynoylphenols compounds, 3a–3e, under moderate conditions. The mechanistic study clearly demonstrated that NNM stabilized the catalytic palladium species, and accelerated the leaving of triazine moiety during the catalytic cycle of the cross-coupling reactions. In addition, piperazine was found to efficiently catalyze the 6-endo cyclization of acylated o-alkynoylphenols, which achieved the diversity oriented synthesis of γ-benzopyranones, 4aa–4eg, with 93–99% yields.
- Yang, Dandan,Wang, Zhenhua,Wang, Xiu,Sun, Huaming,Xie, Zunyuan,Fan, Juan,Zhang, Guofang,Zhang, Weiqiang,Gao, Ziwei
-
-
- Carboxylic acid [...]end alkyne couplingacetylenic ketone the method of preparation
-
The invention discloses a method for preparing acetyenic ketone by coupling carboxylate triazinyl ester with terminal alkyne. According to the method, palladium acetate is taken as a catalyst, and a carboxylate triazinyl ester compound is taken as an elec
- -
-
Paragraph 0014-0017; 0157
(2016/11/21)
-
- Highly Selective and Modular Synthesis of 3-Aryl-4-(arylethynyl)-2H-chromen-2-ones from 2-Iodoaryl 2-Arylacetates through a Carbonylative Sonogashira Coupling–Intramolecular Aldol Cascade Reaction
-
A modular method for the synthesis of 3-aryl-4-(arylethynyl)-2H-chromen-2-ones from 2-iodoaryl 2-arylacetates and arylacetylenes has been developed. The carbonylative Sonogashira coupling–intramolecular aldol casade reaction was carried out in the presence of Pd(PPh3)2(Cl)2as the catalyst. The one-pot approach that involves the in situ formation of the 2-iodoaryl 2-arylacetates from the corresponding 2-iodophenols and 2-arylacetyl chlorides followed by the palladium-catalyzed carbonylative annulation in the presence of the arylacetylene has also been described for the formation of the 3-aryl-4-(arylethynyl)-2H-chromen-2-ones.
- Chandrasekhar, Attoor,Ramkumar, Venkatachalam,Sankararaman, Sethuraman
-
p. 4041 - 4049
(2016/08/24)
-
- Privilege Ynone Synthesis via Palladium-Catalyzed Alkynylation of "Super-Active Esters"
-
A neat palladium-catalyzed alkynylation reaction was developed with "super-active ester" as the carbonyl electrophile, which provides a clean and efficient synthetic protocol for a broad array of ynone compounds under CO-, Cu-, ligand-, and base-free conditions. The superior activity of triazine ester was rationalized by the strong electron-withdrawing ability and the unique affinity of triazine on palladium. A mechanistic experiment clearly demonstrated that the N-Pd coordination of triazine plays a crucial role for the highly efficient C-O activation. (Chemical Equation presented).
- Yu, Bo,Sun, Huaming,Xie, Zunyuan,Zhang, Guofang,Xu, Li-Wen,Zhang, Weiqiang,Gao, Ziwei
-
supporting information
p. 3298 - 3301
(2015/07/15)
-
- A concise synthesis of 3-aroylflavones via Lewis base 9-azajulolidine- catalyzed tandem acyl transfer-cyclization
-
Lewis base-catalyzed tandem acyl transfer-cyclization of acylated o-alkynoylphenols leading to 3-aroylflavones was developed. 9-Azajulolidine smoothly promoted the reaction of the aroyl derivatives at ambient temperature, and the structure-diversed synthesis of 3-aroylflavones with distinct substituents was achieved in moderate to excellent yields.
- Yoshida, Masahito,Saito, Koya,Fujino, Yuta,Doi, Takayuki
-
supporting information
p. 11796 - 11798,3
(2020/10/15)
-
- Synthesis of flavones and γ-benzopyranones using mild sonogashira coupling and 18-crown-6 ether mediated 6-endo cyclization
-
An efficient method for the synthesis of flavones and γ- benzopyranones has been developed utilizing a mild Sonogashira coupling and 18-crown-6 ether mediated 6-endo cyclization of o-alkynoylphenyl acetates. By using this strategy, flavones and γ-benzopyranones bearing electron-donating groups, halogens, and simple alkyl substituents were synthesized in satisfactory yields. A facile, mild, and selective method for the synthesis of flavones and γ-benzopyranones is reported. o-Alkynoylphenyl acetates were obtained from either acyl chloride derivatives or substituted salicylates. Upon removing the acetate group, flavones and γ- benzopyranones were synthesized within 15 min with the aid of 18-crown-6 ether. A library of flavones and γ-benzopyranones was established. Copyright
- Chuang, Da-Wei,El-Shazly, Mohamed,Balaji D., Barve,Chung, Yu-Ming,Chang, Fang-Rong,Wu, Yang-Chang
-
p. 4533 - 4540,8
(2020/08/31)
-