136559-32-5Relevant articles and documents
Micellar-driven substrate selectivity in Cr(salen)Cl catalytic Diels-Alder reaction in water
Trentin, Francesco,Scarso, Alessandro,Strukul, Giorgio
, p. 6978 - 6981 (2011)
A 3.5 increase in catalytic activity was observed in the Cr(III) (salen)Cl 3 catalyzed Diels-Alder reaction between cyclopentadiene 1 with the longer trans-2-decenal 2g compared to the shorter trans-2-butenal 2a dienophile under aqueous micellar conditions, while in chloroform the two substrates react with comparable activities.
Bis-selenonium Cations as Bidentate Chalcogen Bond Donors in Catalysis
He, Xinxin,Wang, Xinyan,Tse, Ying-Lung Steve,Ke, Zhihai,Yeung, Ying-Yeung
, p. 12632 - 12642 (2021/10/21)
Lewis acids are frequently employed in catalysis but they often suffer from high moisture sensitivity. In many reactions, catalysts are deactivated because of the problem that strong Lewis acids also bond to the products. In this research, hydrolytically stable bidentate Lewis acid catalysts derived from selenonium dicationic centers have been developed. The bis-selenonium catalysts are employed in the activation of imine and carbonyl groups in various transformations with good yields and selectivity. Lewis acidity of the bis-selenonium salts was found to be stronger than that of the monoselenonium systems, attributed to the synergistic effect of the two cationic selenonium centers. In addition, the bis-selenonium catalysts are not inhibited by strong bases or moisture.
Synthesis of cis-Hedione and methyl jasmonate via cascade Baylis-Hillman reaction and Claisen ortho ester rearrangement
Chapuis, Christian,Buechi, George H.,Wueest, Hans
, p. 3069 - 3088 (2007/10/03)
The exocyclically unsaturated conjugated keto esters 10, obtained via a Claisen ortho ester rearrangement of the allylic hydroxy ketones 9, were either directly hydrogenated or partially isomerized into the endocyclically unsaturated tetrasubstituted didehydrojasmonoid intermediates 14, prior to a more selective hydrogenation with Pd/C in cyclohexane to the disubstituted oxocyclopentaneacetates 15 (Scheme 2). The key intermediates 9 were obtained either by a four-step sequence, including acetal protection/deprotection from enone 1, in the specific case of hydroxy ketone 9a (Scheme 1), or more directly and generally by a Baylis-Hillman reaction from cyclopent-2-en-1-one (16) and the appropriate aldehydes 17 (Scheme 2). The judicious choice of these aldehydes opens versatile modifications for the stereoselective introduction of the partially cis- or epimerized trans-C(2) jasmonoid side chain, while the Baylis-Hillman reaction, catalyzed by chiral [1,1′-binaphthalene]-2, 2′-diols (BINOLs) 19 (Scheme 3), may be efficiently conducted in a one-pot cascade fashion including the ortho ester Claisen rearrangement.
