87328-17-4Relevant academic research and scientific papers
Method for synthesizing polysubstituted cyclopropane through photocatalysis of olefin cyclopropanation reaction
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Paragraph 0013; 0024-0026, (2020/04/29)
The invention discloses a method for synthesizing polysubstituted cyclopropane through photocatalysis of an olefin cyclopropanation reaction. The method comprises the following steps: adding a stirrer, polysubstituted olefin, Ir[dF(CF3)ppy]2(dtbbpy)PF6 and bromomethyl bis(catechol)silicate-18-crown ether-6-potassium into a reaction tube, vacuumizing, exchanging nitrogen, and injecting dimethyl sulfoxide; putting the reaction tube into blue light, stirring for 24 hours under the condition of illumination at room temperature, and extracting after the reaction is finished; and drying, carrying out column chromatography separation, and distilling to obtain polysubstituted cyclopropane. According to the invention, the method has the advantages of single reaction product, wide substrate universality, high functional group compatibility, mild reaction conditions and the like.
Bromomethyl Silicate: A Robust Methylene Transfer Reagent for Radical-Polar Crossover Cyclopropanation of Alkenes
Luo, Wenping,Fang, Yewen,Zhang, Li,Xu, Tianhang,Liu, Yongjun,Li, Yan,Jin, Xiaoping,Bao, Jiakan,Wu, Xiaodong,Zhang, Zongyong
supporting information, p. 1778 - 1781 (2020/03/11)
A general protocol for visible-light-induced cyclopropanation of alkenes was developed with bromomethyl silicate as a methylene transfer reagent, offering a robust tool for accessing highly valuable cyclopropanes. In addition to α-aryl or methyl-substituted Michael acceptors and styrene derivatives, the unactivated 1,1-dialkyl ethylenes were also shown to be viable substrates. Apart from realizing the cyclopropanation of terminal alkenes, the methyl transfer reaction has been further demonstrated to be amenable to the internal olefins. The photocatalytic cyclopropanation of 1,3-bis(1-arylethenyl)benzenes was also achieved, giving polycyclopropane derivatives in excellent yields. With late-stage cyclopropanation as the key strategy, the synthetic utility of this transformation was also demonstrated by the total synthesis of LG100268.
Redox-Neutral Photocatalytic Cyclopropanation via Radical/Polar Crossover
Phelan, James P.,Lang, Simon B.,Compton, Jordan S.,Kelly, Christopher B.,Dykstra, Ryan,Gutierrez, Osvaldo,Molander, Gary A.
supporting information, p. 8037 - 8047 (2018/07/03)
A benchtop stable, bifunctional reagent for the redox-neutral cyclopropanation of olefins has been developed. Triethylammonium bis(catecholato)iodomethylsilicate can be readily prepared on multigram scale. Using this reagent in combination with an organic photocatalyst and visible light, cyclopropanation of an array of olefins, including trifluoromethyl- and pinacolatoboryl-substituted alkenes, can be accomplished in a matter of hours. The reaction is highly tolerant of traditionally reactive functional groups (carboxylic acids, basic heterocycles, alkyl halides, etc.) and permits the chemoselective cyclopropanation of polyolefinated compounds. Mechanistic interrogation revealed that the reaction proceeds via a rapid anionic 3-exo-tet ring closure, a pathway consistent with experimental and computational data.
Visible-Light-Promoted Redox-Neutral Cyclopropanation Reactions of α-Substituted Vinylphosphonates and Other Michael Acceptors with Chloromethyl Silicate as Methylene Transfer Reagent
Guo, Ting,Zhang, Li,Liu, Xiaobo,Fang, Yewen,Jin, Xiaoping,Yang, Yi,Li, Yan,Chen, Bin,Ouyang, Minghui
supporting information, p. 4459 - 4463 (2018/09/14)
The alkene cyclopropanation with chloromethyl silicate as a methylene transfer reagent has been accomplished via visible-light-mediated redox-neutral catalysis. This method features broad functional group tolerance and mild conditions. In addition to α-substituted vinylphosphonates, a range of Michael acceptors including α,β-unsaturated acrylate, ketone, amide and sulfone are suitable substrates for this photocatalytic cyclopropanation. An application of this protocol to the cyclopropanation of estrone derivative is also presented. (Figure presented.).
Deamination Reactions, 45. Decomposition of 1-Arylcyclopropanediazonium Ions
Kirmse, Wolfgang,Rode, Jutta
, p. 3694 - 3703 (2007/10/02)
1-Arylcyclopropanediazonium ions have been generated by alkaline cleavage of the analogous nitrosocarbamates in methanol.With increasing ?-donor capacity of the aryl groups, retention of the three-membered ring was enhanced while the stereoselectivity (as probed with the aid of 2-D labels) was diminished or entirely lost (4-methoxyphenyl).Where applicable, the stereoselectivity of ring opening is inferior to that of nucleophilic displacement.The data may be interpreted in terms of competing reactions (ks, kc, kΔ) of the cyclopropanediazonium ions.
LACTONIZATION OF PHENYLCYCLOPROPANECARBOXYLIC ACIDS
Sychkova, L. D.,Kharitonova, O. V.,Shabarov, Yu. S.
, p. 1298 - 1301 (2007/10/02)
The capacity of phenylcyclopropanecarboxylic acids for lactonization under the influence of mineral acids was studied.It was found that concentrated sulfuric acid at 20 deg C can give rise to lactonization only in the case where the intermediately formed carbocation is stabilized by a phenyl group.Preliminary isomerization to the corresponding unsaturated acid does not occur here.
