27644-03-7Relevant academic research and scientific papers
An improved and practical synthesis route to antiproliferative (±)-shikonin and its O-acyl derivatives
Ono, Mana,Abe, Shouki,Higai, Koji,Higashi, Shoko,Saito, Setsuo,Saito, Ryota
, p. 738 - 746 (2020/12/09)
Shikonin and its O-acyl derivatives are attracting increasing levels of attention among medicinal chemists due to their potencies as highly selective cytotoxic agents against cancer cells. However, providing a large number of shikonin-related samples by organic synthesis remains challenging. In the present study, we developed an improved and practical synthesis route to shikonin derivatives by olefin metathesis that has enabled the gram-scale preparation of a prenylated tetramethylnaphthazaline, a key intermediate in the synthesis of shikonin. In addition, a method for the selective cleavage of the acyl protecting groups at the phenolic positions of tri-O-acylated shikonins has been developed that provides concise routes to diverse O-acylshikonin derivatives.
Catalytic asymmetric aldehyde prenylation and application in the total synthesis of (-)-rosiridol and (-)-bifurcadiol
Huang, Yi-Yong,Kalita, Subarna Jyoti,Li, Jing-Jie,Li, Wang-Lai,Schneider, Uwe,Zhang, Yu-Long,Zhao, Zhen-Ni
, p. 10030 - 10033 (2020/09/15)
Chiral phosphoric acid-catalyzed asymmetric aldehyde prenylation has been established using an α,α-dimethyl allyl boronic ester. The transformation provides expedient access to a wide array of aryl, heteroaryl, aryl-substituted alkenyl and primary and sec
Hydroxy-directed, fluoride-catalyzed epoxide hydrosilylation for the synthesis of 1,4-diols
Zhang, Yong-Qiang,Funken, Nico,Winterscheid, Peter,Gans?uer, Andreas
supporting information, p. 6931 - 6934 (2015/06/08)
Abstract A novel highly regioselective, fluoride-catalyzed hydrosilylation of β-hydroxy epoxides has been developed. The reaction is modular and applicable to the synthesis of a broad range of 1,4-diols. Fluoride is crucial for two reasons: First, it promotes the formation of a silyl ether (which contains a Si-H bond) and, second, it enables ring opening by an intramolecular SN2 reaction through activation of the silane. The reaction can be performed under air. A modular, convergent, and stereoselective synthesis of 1,4-diols by epoxide hydrosilylation has been developed (see scheme). The reaction occurs under fluoride catalysis, is high yielding, highly regioselective, and can be carried out on a large scale.
Highly regioselective and chemoselective titanocene mediated Barbier-type allylation reactions
Morcillo, Sara P.,Martinez-Peragon, Angela,Jakoby, Verena,Mota, Antonio J.,Kube, Christian,Justicia, Jose,Cuerva, Juan M.,Gansaeuer, Andreas
supporting information, p. 2211 - 2213 (2014/02/14)
Titanocene carboxylate 1 is an excellent chemoselective reagent for unprecedented α-regioselective Barbier-type reactions. It constitutes the first titanocene(iii) able to tolerate epoxides and readily reduced carbonyl compounds, such as aromatic and α,β-unsaturated aldehydes. The Royal Society of Chemistry.
Prins cyclization of α-bromoethers under basic conditions
Arpin, Patrice,Hill, Bryan,Larouche-Gauthier, Robin,Spino, Claude
, p. 1193 - 1201 (2014/01/06)
α-Bromoethers have been found to undergo Prins-type cyclization under basic conditions and without the need to add a promoter. The products are those derived from a Markovnikov addition on the pendant alkene. However, the stereochemistry and even the structure of the products sometimes differ from those expected with the classical Lewis-acid-catalyzed Prins reaction of acetals.
Product selectivity control induced by using liquid-liquid parallel laminar flow in a microreactor
Amemiya, Fumihiro,Matsumoto, Hideyuki,Fuse, Keishi,Kashiwagi, Tsuneo,Kuroda, Chiaki,Fuchigami, Toshio,Atobe, Mahito
scheme or table, p. 4256 - 4265 (2011/07/29)
Product selectivity control based on a liquid-liquid parallel laminar flow has been successfully demonstrated by using a microreactor. Our electrochemical microreactor system enables regioselective cross-coupling reaction of aldehyde with allylic chloride via chemoselective cathodic reduction of substrate by the combined use of suitable flow mode and corresponding cathode material. The formation of liquid-liquid parallel laminar flow in the microreactor was supported by the estimation of benzaldehyde diffusion coefficient and computational fluid dynamics simulation. The diffusion coefficient for benzaldehyde in Bu4NClO4-HMPA medium was determined to be 1.32 × 10-7 cm2 s-1 by electrochemical measurements, and the flow simulation using this value revealed the formation of clear concentration gradient of benzaldehyde in the microreactor channel over a specific channel length. In addition, the necessity of the liquid-liquid parallel laminar flow was confirmed by flow mode experiments.
Chemoselective reaction system using a two inlet micro-flow reactor: Application to carbonyl allylation
Amemiya, Fumihiro,Fuse, Keishi,Fuchigami, Toshio,Atobe, Mahito
supporting information; experimental part, p. 2730 - 2732 (2010/09/04)
A new strategy for chemoselective reaction using a two inlet micro-flow reactor is described. In this system, the combined use of suitable flow mode and corresponding cathode material enables chemoselective cathodic reduction to control the product regios
Pt-catalyzed tandem 1,2-acyloxy migration/intramolecular [3 + 2] cycloaddition of enynyl esters
Zheng, Huaiji,Zheng, Jiyue,Yu, Binxun,Chen, Qiang,Wang, Xiaolei,He, Yongping,Yang, Zhen,She, Xuegong
supporting information; experimental part, p. 1788 - 1789 (2010/04/23)
(Formula Presented) A platinum-catalyzed tandem reaction involving enynyl ester isomerization and subsequent intramolecular [3 + 2] cyclization has been developed. This strategy provides an efficient approach to five-, six-, or seven-membered cyclic polyfunctional compounds. Copyright
New and stereoselective synthesis of 1,4-disubstituted buten-4-ols (homoallylic alcohol α-adducts) from the corresponding γ-isomers (3,4-disubstituted buten-4-ols) via an acid-catalyzed allyl-transfer reaction with aldehydes
Sumida, Shin-Ichi,Ohga, Masanori,Mitani, Junji,Nokami, Junzo
, p. 1310 - 1313 (2007/10/03)
The γ-adducts of homoallylic alcohols 3, derived from aldehydes via the usual reaction with common allylic metals 1, were converted to the corresponding α-adducts 6 by an acid-catalyzed allyl-transfer reaction. In the allyl-transfer reaction, anti-and syn
Solvolysis of 1-[trans-2-(m- Orp-Substituted Phenyl)cyclopropyl]- 1-methylethyl p-Nitrobenzoates
Kusuyama, Yoshiaki
, p. 685 - 691 (2007/10/03)
The solvolyses of 1-[trans-2-(m- or p-substituted phenyl)cyclopropyl]-1-methylethyl p-nitrobenzoates in 80% aqueous acetone have been studied with regard to both reactivity and product composition. For the less reactive substituents such as m-Br, m-Cl, and m-CF3, the solvolysis products were the corresponding 2-(2-arylcyclopropyl)-2-propanol, indicating the cyclopropylmethyl cation intermediate. The ring-opened products increased as the electron-donating ability of the substituents increased. The application of the Yukawa-Tsuno equation to the reactivity afforded a ρ value of -1.43 and r value of 0.59 with a correlation coefficient of 0.997. A large value of r indicates the presence of the allylic cation intermediate where much more charge develops at the benzylic carbon for the derivatives with electron-donating substituents than is the case for the cyclopropylmethyl cation intermediate. Thus the solvolysis reaction proceeds via two independent pathways: one has a cyclopropyl cation intermediate and the other has a homoallylic cation intermediate.
