- Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
-
An unprecedented C═C double bond cleavage of cyclopropenone and dioxygen activation by multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fully substituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.
- Yao, Liangliang,Hu, Qiong,Bao, Li,Zhu, Wenjing,Hu, Yimin
-
supporting information
p. 4971 - 4975
(2021/06/30)
-
- Iron-Catalyzed One-Step Synthesis of Isothiazolone/1,2-Selenazolone Derivatives via [3+1+1] Annulation of Cyclopropenones, Anilines, and Elemental Chalcogens
-
Described herein is the one-step synthesis of isothiazolone/1,2-selenazolone derivatives via [3+1+1] cycloaddition of cyclopropenone derivatives, anilines, and elemental chalcogens. The cascade reaction involves the C?S, C?N, and N?S bond formation along with the cleavage of C?C bond. Both anilines and cyclopropenones are tolerated and give the corresponding products in 28–73% yields. (Figure presented.).
- Wang, Hongchen,Yan, Rulong
-
supporting information
(2021/12/22)
-
- Organocatalytic Regiodivergent C?C Bond Cleavage of Cyclopropenones: A Highly Efficient Cascade Approach to Enantiopure Heterocyclic Frameworks
-
Here a highly efficient cascade approach is reported that combines a cycloaddition reaction with a regioselective strain-release process to afford diverse heterocyclic frameworks through bifunctional catalysis. The cooperation of hydrogen-bonding network activation and a regiodivergent strain-assisted effect is the key to promoting this complex chemical transformation, leading to the generation of two different ring systems in high yields with excellent stereoselectivities. The reaction proceeded by a mechanism involving a “spring-loaded” intermediate with switchable C?C bond cleavages achieved by controllable ring-strain release. This reaction was also amenable to gram scale synthesis with only 0.1 mol % catalyst loading.
- Cao, Jian,Fang, Ran,Liu, Jin-Yu,Lu, Hong,Luo, Yong-Chun,Xu, Peng-Fei
-
supporting information
p. 18863 - 18867
(2018/11/23)
-
- Organocatalyzed [3 + 2] Annulation of Cyclopropenones and β-Ketoesters: An Approach to Substituted Butenolides with a Quaternary Center
-
An unprecedented organocatalyzed [3 + 2] annulation of cyclopropenones and β-ketoesters has been developed. This reaction provides a direct approach to highly substituted butenolides with a quaternary center in moderate to good yields. The preliminary mechanism study verified that the enol intermediate is crucial to the reaction outcome and the intermolecular esterification and intramolecular Michael addition process were involved.
- Li, Xuanyi,Han, Chunhua,Yao, Hequan,Lin, Aijun
-
supporting information
p. 778 - 781
(2017/03/01)
-
- Cyclopropenone catalyzed substitution of alcohols with mesylate ion
-
The cyclopropenone catalyzed nucleophilic substitution of alcohols by methanesulfonate ion with inversion of configuration is described. This work provides an alternative to the Mitsunobu reaction that avoids the use of azodicarboxylates and generation of hydrazine and phosphine oxide byproducts. This transformation is shown to be compatible with a range of functionality. A cyclopropenone scavenge strategy is demonstrated to aid purification.
- Nacsa, Eric D.,Lambert, Tristan H.
-
supporting information
p. 38 - 41
(2013/03/28)
-
- Cyclopropenium-activated cyclodehydration of diols
-
The dehydrative cyclization of diols to cyclic ethers via cyclopropenium activation is described. Using 2,3-diphenylcyclopropene and methanesulfonic anhydride, a series of 1,4-and 1,5-diols are rapidly cyclized to furnish tetrahydrofurans and tetrahydropyrans in high yield. Eleven total substrates are shown, including a gram scale cyclization of a diterpene derivative.
- Kelly, Brendan D.,Lambert, Tristan H.
-
supporting information; experimental part
p. 740 - 743
(2011/05/04)
-
- Aromatic cation activation of alcohols: Conversion to alkyl chlorides using dichlorodiphenylcyclopropene
-
(Chemical Equation Presented) A novel paradigm for the activation of alcohols toward nucleophilic displacement via formation of cyclopropenium ethers is described. The conversion of a range of alcohol substrates to the corresponding alkyl chlorides occurs rapidly upon treatment with 3,3-dichloro-1,2-diphenylcyclopropene. 1H NMR data support the intermediacy of a cyclopropenium intermediate, and the reaction is demonstrated to proceed primarily via the SN2 mechanism for 1-phenylethanol. A total of 12 examples of substrate scope are provided.
- Kelly, Brendan D.,Lambert, Tristan H.
-
supporting information; experimental part
p. 13930 - 13931
(2009/12/25)
-