35376-40-0Relevant academic research and scientific papers
Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones
Beltran, Frédéric,Bergamaschi, Enrico,Funes-Ardoiz, Ignacio,Teskey, Christopher J.
, p. 21176 - 21182 (2020/09/17)
Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their “hard” or “soft” character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of α,β-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.
An unexpected and significantly lower hydrogen-bond-donating capacity of fluorohydrins compared to nonfluorinated alcohols
Graton, Jerome,Wang, Zhong,Brossard, Anne-Marie,Goncalves Monteiro, Daniela,Le Questel, Jean-Yves,Linclau, Bruno
supporting information; experimental part, p. 6176 - 6180 (2012/08/14)
Rewriting the rules as fluorination does not always increase hydrogen-bond acidity: while the strongly electron-withdrawing fluorine significantly enhances alcohol H-bond acidity in anti-vicinal fluorohydrins, an intramolecular F...HO interaction overrule
Origins of Regio- and Stereoselectivity in Additions of Phenylselenenyl Chloride to Allylic Alcohols and the Applicability of These Additions to a Simple 1,3-Enone Transposition Sequence
Liotta, Dennis,Zima, George,Saindane, Manohar
, p. 1258 - 1267 (2007/10/02)
The regio- and stereoselectivity of phenylselenenyl chloride additions to allylic alcohols and their derivatives have been systematically studied.On the basis of the results, a mechanism involving two basic premises is proposed.These are as follows: (a) allylic oxygen's direct selenonium ion formation to the syn face of the double bond; (b) axial attack of the chloride ion is kinetically favored over equatorial attack.A series of rules which are useful for predicting the regio- and stereoselectivity of phenylselenenyl chloride additions to allylic systems are discussed.In addition, these reactions can be used as the key step in a general 1,3-enone transposition sequence.Several examples of this transposition sequence are illustrated.
