20574-98-5Relevant articles and documents
TiO2 Photocatalysis in Aromatic "redox Tag"-Guided Intermolecular Formal [2 + 2] Cycloadditions
Okada, Yohei,Maeta, Naoya,Nakayama, Kaii,Kamiya, Hidehiro
, p. 4948 - 4962 (2018)
Since the pioneering work by Macmillan, Yoon, and Stephenson, homogeneous photoredox catalysis has occupied a central place in new reaction development in the field of organic chemistry. While heterogeneous semiconductor photocatalysis has also been studied extensively, it has generally been recognized as a redox option in inorganic chemistry where such "photocatalysis" is most often used to catalyze carbon-carbon bond cleavage and not in organic chemistry where bond formation is usually the focal point. Herein, we demonstrate that titanium dioxide photocatalysis is a powerful redox option to construct carbon-carbon bonds by using intermolecular formal [2 + 2] cycloadditions as models. Synergy between excited electrons and holes generated upon irradiation is expected to promote the overall net redox neutral process. Key for the successful application is the use of a lithium perchlorate/nitromethane electrolyte solution, which exhibits remarkable Lewis acidity to facilitate the reactions of carbon-centered radical cations with carbon nucleophiles. The reaction mechanism is reasonably understood based on both intermolecular and intramolecular single electron transfer regulated by an aromatic "redox tag". Most of the reactions were completed in less than 30 min even in aqueous and/or aerobic conditions without the need for sacrificial reducing or oxidizing substrates generally required for homogeneous photoredox catalysis.
Catalytic δ-hydroxyalkynone rearrangement in the stereoselective total synthesis of centrolobine, engelheptanoxides A and C and analogues
Ahmad, Mohammad N.,Chopra, Sidharth,Fernandes, Rodney A.,Kumar, Praveen
, (2021/08/13)
A catalytic stereoselective total synthesis of centrolobine and engelheptanoxides A and C has been completed via a metal-free catalytic δ-hydroxyalkynone rearrangement to 2,3-dihydro-4H-pyran-4-one and diastereoselective hydrogenation to the all syn-2,4,6-trisubstituted pyran strategy. The onliest required chirality was introduced by Jacobsen kinetic resolution, which further directed the diastereoselective hydrogenation. A first stereoselective synthesis of engelheptanoxide A is also accomplished. The analogues and derivatives of centrolobine and engelheptanoxides prepared were evaluated for antitubercular activity against M. tuberculosis H37Rv ATCC 27294.
Method for preparing olefin compound under alkaline condition
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Paragraph 0024-0026, (2021/05/29)
The invention relates to a method for preparing an olefin compound under an alkaline condition. The method comprises the following steps: adding a solvent and an alkali catalyst into long-chain alcohol serving as a raw material, introducing sulfuryl fluoride gas, stirring for reaction, and separating and purifying to obtain the olefin compound. The olefin compound has a structural formula shown in the description; and in the formula, R is phenyl, substituted phenyl, heterocyclic aryl, fused ring aryl, substituted fused ring aryl or alkyl. An alkali-promoted alcohol-to-olefin conversion method developed by the invention is mild in reaction condition, simple and convenient to operate and low in instrument and equipment requirements, the long-chain alcohol is used as a reaction raw material, the price is low, the source is wide, and the yield of the prepared olefin compound is high; and the method effectively avoids the influence of acidic conditions on part of groups (acetal, ketal, epoxy and the like), is efficient in reaction and wide in substrate application range, can tolerate most of functional groups, and provides a new path for synthesis of complex olefins.
