Chiral Pyrroline-Based Ugi-Three-Component Reactions Are under Kinetic Control
作者:Erwin R. van Rijssel、Theodorus P. M. Goumans、Gerrit Lodder、Herman S. Overkleeft、Gijsbert A. van der Marel、Jeroen D. C. Codée
DOI:10.1021/ol4012053
日期:2013.6.21
is often assumed that the stereochemistry in Ugi multicomponent reactions is determined in the final Mumm rearrangement step, experimental and computational evidence that Ugi reactions on hydroxylated pyrrolines proceed under kinetic control is reported. The stereochemistry of the reaction is established with the addition of the isocyanide to the intermediate iminium ion, whose conformation is determined
The invention relates to azabenzofuranyl compounds of Formula I with anti-cancer and/or anti-inflammatory activity and more specifically to azabenzofuranyl compounds which inhibit MEK kinase activity. The invention provides compositions and methods useful for inhibiting abnormal cell growth or treating a hyperproliferative disorder, or treating an inflammatory disease in a mammal. The invention also relates to methods of using the compounds for in vitro, in situ, and in vivo diagnosis or treatment of mammalian cells, or associated pathological conditions.
Stereospecific Furanosylations Catalyzed by Bis-thiourea Hydrogen-Bond Donors
作者:Andrew B. Mayfield、Jan B. Metternich、Adam H. Trotta、Eric N. Jacobsen
DOI:10.1021/jacs.0c00335
日期:2020.2.26
We report a new method for stereoselective O-furanosylation reactions promoted by a precisely tailored bis-thiourea hydrogen-bond-donor catalyst. Furanosyl donors outfitted with an anomeric dialkylphosphate leaving group undergo substitution with high anomeric selectivity, providing access to the challenging 1,2-cis substitution pattern with a range of alcohol acceptors. A variety of stereochemically distinct, benzyl-protected glycosyl donors were engaged successfully as substrates. Mechanistic studies support a stereospecific mechanism in which rate-determining substitution occurs from a catalyst-donor resting-state complex.
Syntheses with Partially Benzylated Sugars. II.<sup>1</sup> The Anomeric 1-O-Benzoyl-L-arabinopyranoses and 1-O-Benzoyl-L-arabinofuranoses and Their Tendencies to Undergo Acyl Migration
作者:Setsuzo Tejima、Hewitt G. Fletcher
DOI:10.1021/jo01046a015
日期:1963.11
FINCH, PAUL;ISKANDER, GEORGE M.;SIRIWARDENA, ALOYSIUS H., CARBOHYDR. RES., 210,(1991) C. 319-325
作者:FINCH, PAUL、ISKANDER, GEORGE M.、SIRIWARDENA, ALOYSIUS H.