934569-81-0Relevant articles and documents
Trifluorosulfonylation Cascade in Allenols: Stereocontrolled Synthesis of Bis(triflyl)enones
Lázaro-Milla, Carlos,Macicior, Jon,Yanai, Hikaru,Almendros, Pedro
, p. 8983 - 8989 (2020)
Herein, we report investigations embodying the first example of reversal of the native regioselectivity in the reaction of allenols with electrophiles. The effortlessness of C?C bond formation, mild reaction conditions, neither catalysts nor light irradiation, and exquisite selectivity, both in terms of functional-group tolerance and chemo-, site-, and stereo-selectivity, converts this trifluorosulfonylation-rearrangement sequence into an appealing protocol for the preparation of novel functionalized enones. The synthetic utility of this method has been validated by the conversion of the initially prepared bis(triflyl)enones into a variety of bis(triflyl)-functionalized molecules such as 1,3-dienes, allylic alcohols, pyrroles, pyrazoles, and chromenes. Besides, DFT calculations have provided a reliable understanding of observed selectivity.
Steric buttressing in the Pauson-Khand reactions of benzyl enynes
Madu, Christian E.,Dias, H.V. Rasika,Lovely, Carl J.
, p. 6118 - 6137 (2017/09/29)
The application of the intramolecular Pauson-Khand reaction of 1,n-enynes provides a convenient method for the construction of polycyclic frameworks but this process has largely been limited to the formation of 5,5- and 5,6-fused ring systems. In this report, we describe the application of the Pauson-Khand cyclization to 1,8-enynes embedded in an aromatic ring system wherein it is determined that the presence of steric buttresses in the form of t-butyl groups facilitates the cycloaddition. These reactions proceed in good yields with either thermal or oxidative activation and in the former case, the diastereoselectivities are high. An investigation of the tolerance of this cycloaddition to substitution around the 1,8-enyne demonstrates that only 2,2-disubstitution does not result in productive cyclization. Cycloadditions with hydroxyl groups at the propargylic position while leading to fused rings are compromised by side reactions leading to reduction and in some cases tautomerization. However, these byproducts are easily minimized through conversion of the hydroxyl group to the corresponding silyl ether.
Electrophilic carbon transfer in gold catalysis: Synthesis of substituted chromones
Renault, Jacques,Qian, Zhao,Uriac, Philippe,Gouault, Nicolas
, p. 2476 - 2479 (2011/05/16)
Using easily accessible aromatic alkoxy-arylalkynones, we have investigated the gold-catalyzed intramolecular addition of ethers to alkynes, to give easy access to various substituted chromones. This reaction involves the transfer of the ether substituent via a carbodemetallation process. We also noticed a competing isomerization of several starting materials for which we propose a second gold catalyzed mechanism.
