1074-15-3Relevant articles and documents
Synthesis of 2,3-dihydro-1-phenylbenzo[b]phosphole (1-phenylphosphindane) and its use as a mechanistic test in the asymmetric appel reaction: Decisive evidence against involvement of pseudorotation in the stereoselecting step
Carr, Damien J.,Kudavalli, Jaya Satyanarayana,Dunne, Katherine S.,Mueller-Bunz, Helge,Gilheany, Declan G.
, p. 10500 - 10505 (2013)
Racemic 2,3-dihydro-1-phenylbenzo[b]phosphole was obtained by reduction of 1-phenylbenzo[b]phosphole-1-oxide, itself derived by ring-closing metathesis of phenylstyrylvinylphosphine oxide. The title compound was then reoxidized under asymmetric Appel cond
Enantio- and diastereotopos differentiation in the palladium(II)-catalyzed hydrosilylation of bicyclo[2.2.1]alkene scaffolds with silicon-stereogenic silanes
Rendler, Sebastian,Froehlich, Roland,Keller, Manfred,Oestreich, Martin
, p. 2582 - 2591 (2008)
The palladium(II)-catalyzed hydrosilylation of meso-configured bicyclo[2.2.1]alkene scaffolds proved to be an invaluable model reaction for the development of reagent-controlled asymmetric transformations based on silicon-stereogenic silanes as stereoinducers. In the present investigation, the subtle structural requirements of the silane substitution pattern in enantiotopos-differentiating single hydrosilylations of a norbornene-type substrate are disclosed. Extension of this chemistry to a double hydrosilylation of norbornadiene entails a significant increase in stereochemical complexity. Although differentiation of enantiotopic positions by the chiral reagent is demanded in the first hydrosilylation, the same reagent must then differentiate diastereotopic positions in the second. Remarkably high stereocontrol was found in this double hydrosilylation with several silanes first used in the hydrosilylations of the norbornene-type system. Depending on the enantiomeric purity of the silane, C2- and Cs-symmetric adducts, respectively, were obtained. The identity of the key quaternary silanes was revealed by crystallographic analysis. By this method, the relative and absolute configurations were also assigned, which, in turn, imply that all enantiospecific substitutions at silicon proceed with stereoretention. On the basis of these solid-state structures, we also discuss the structural implications of silane substitution for the diastereoselectivity-determining step of this palladium(II)-catalyzed hydrosilylation reaction. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Synthesis and Structure-Affinity Relationships of Spirocyclic Benzopyrans with Exocyclic Amino Moiety
Kronenberg, Elisabeth,Weber, Frauke,Brune, Stefanie,Schepmann, Dirk,Almansa, Carmen,Friedland, Kristina,Laurini, Erik,Pricl, Sabrina,Wünsch, Bernhard
supporting information, p. 4204 - 4217 (2019/05/06)
σ1 and/or σ2 receptors play a crucial role in pathological conditions such as pain, neurodegenerative disorders, and cancer. A set of spirocyclic cyclohexanes with diverse O-heterocycles and amino moieties (general structure III) was prepared and pharmacologically evaluated. In structure-activity relationships studies, the σ1 receptor affinity and σ1:σ2 selectivity were correlated with the stereochemistry, the kind and substitution pattern of the O-heterocycle, and the substituents at the exocyclic amino moiety. cis-configured 2-benzopyran cis-11b bearing a methoxy group and a tertiary cyclohexylmethylamino moiety showed the highest σ1 affinity (Ki = 1.9 nM) of this series of compounds. In a Ca2+ influx assay, cis-11b behaved as a σ1 antagonist. cis-11b reveals high selectivity over σ2 and opioid receptors. The interactions of the novel σ1 ligands were analyzed on the molecular level using the recently reported X-ray crystal structure of the σ1 receptor protein. The protonated amino moiety forms a persistent salt bridge with E172. The spiro[benzopyran-1,1′-cyclohexane] scaffold and the cyclohexylmethyl moiety occupy two hydrophobic pockets. Exchange of the N-cyclohexylmethyl moiety by a benzyl group led unexpectedly to potent and selective μ-opioid receptor ligands.
Highly diastereoselective synthesis of tetralin-fused spirooxindoles via lewis acid-catalyzed C(sp3)H bond functionalization
Machida, Mizuki,Mori, Keiji
supporting information, p. 868 - 871 (2018/07/03)
A highly diastereoselective synthesis of tetralin-fused spirooxindole derivatives was described. Treatment of benzylidene oxindoles with a catalytic amount of Sc(OTf)3 in refluxing hexane afforded the target compounds in good chemical yields with excellent diastereoselectivities (up to >20:1). Detailed investigation of the reaction mechanism revealed that both interconversion of the two diastereomers and their solubility difference in reaction medium were the key to achieving excellent diastereoselectivities.