261506-10-9Relevant articles and documents
Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of Propargylic Ketones
Shatskiy, Andrey,Kivij?rvi, Tove,Lundberg, Helena,Tinnis, Fredrik,Adolfsson, Hans
, p. 3818 - 3821 (2016/01/25)
The asymmetric transfer hydrogenation of α,β-propargyl ketones catalyzed by an in situ formed ruthenium-hydroxyamide complex was explored. The acetylenic alcohols were isolated in good to excellent yields with excellent ee values (typically >90 %) after s
Catalytic asymmetric enyne addition to aldehdyes and Rh(I)-catalyzed stereoselective domino Pauson-Khand/[4 + 2] cycloaddition
Chen, Wei,Tay, Jia-Hui,Ying, Jun,Yu, Xiao-Qi,Pu, Lin
, p. 2256 - 2265 (2013/04/24)
The 1,1′-bi-2-naphthol-ZnEt2-Ti(OiPr) 4-Cy2NH system is found to catalyze the 1,3-enyne addition to aliphatic aldehydes as well as other aldehydes at room temperature with 75-96% yield and 82-97% ee. This system is also broadly applicable for the highly enantioselective reaction of other alkyl-, aryl-, and silylalkynes with structurally diverse aldehydes. The propargylic alcohols prepared from the catalytic asymmetric enyne addition to aliphatic aldehydes are used to prepare a series of optically active trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the optically active trienynes undergo highly stereoselective domino Pauson-Khand/[4 + 2] cycloaddition to generate optically active multicyclic products. The Rh(I) catalyst is also found to catalyze the coupling of a diyne with CO followed by [4 + 2] cycloaddition to generate an optically active multicyclic product. These transformations are potentially useful for the asymmetric synthesis of polyquinanes containing a quaternary chiral carbon center.
Catalytic asymmetric synthesis of chiral propargylic alcohols for the intramolecular Pauson-Khand cycloaddition
Turlington, Mark,Yue, Yang,Yu, Xiao-Qi,Pu, Lin
supporting information; experimental part, p. 6941 - 6952 (2010/11/18)
Several methods for the catalytic asymmetric alkyne addition to aldehydes are used to prepare the propargylic alcohol-based chiral en-ynes. Protection of the propargylic alcohols with either an acetyl or a methyl group allows the resulting en-ynes to undergo the intramolecular Pauson-Khand reaction to form the corresponding optically active 5,5- and 5,6-fused bicyclic products with high diastereoselectivity and high enantiomeric purity. In the major product, the propargylic substituent and the bridgehead hydrogen are cis with respect to each other on the fused bicyclic rings. The enantiomeric purity of the propargylic alcohols generated from the asymmetric alkyne addition is maintained in the cycloaddition products. The allylic ethers of the chiral propargylic alcohols are prepared which can also undergo the highly diastereoselective Pauson-Khand cycloaddition with retention of the high enantiomeric purity. This study has shown that the size of the substituents at the propargylic position as well as on the alkyne is important for the diastereoselectivity with the greater bulkiness of the substituents giving higher diastereoselectivity.
