does not cohere with the conventional logic of metathesis, according to which macrocycles are best closed at a disubstituted olefinic site; rather, the trisubstituted C11−C12 alkene flanked by an allylic ‐OH group served as the pivot point for synthesis. This motif was attained in good yield and excellent selectivity by a sequence of alkyne metathesis, trans‐hydrostannation and cross coupling. Because
Sensing Remote Chirality: Stereochemical Determination of β-, γ-, and δ-Chiral Carboxylic Acids
作者:Marina Tanasova、Mercy Anyika、Babak Borhan
DOI:10.1002/anie.201410371
日期:2015.3.27
nonfunctionalizable stereocenters is a challenging task. Presented is a solution in which appropriately substituted bis(porphyrin) tweezers are used. Complexation of a suitably derivatized β‐, γ‐, or δ‐chiralcarboxylicacid to the tweezer induces a predictable helicity of the bis(porphyrin), which is detected as a bisignate Cotton Effect (ECCD). The sign of the ECCD curve is correlated with the absolute
Development and application of versatile bis-hydroxamic acids for catalytic asymmetric oxidation
作者:Allan U. Barlan、Wei Zhang、Hisashi Yamamoto
DOI:10.1016/j.tet.2007.03.071
日期:2007.7
preliminary results of our new designed C(2)-symmetric bis-hydroxamic acid (BHA) ligands and the application of the new ligands for vanadium-catalyzed asymmetric epoxidation of allylic alcohols as well as homoallylic alcohols. From this success we demonstrate the versatile nature of BHA in the molybdenum catalyzed asymmetric oxidation of unfunctionalized olefins and sulfides.
Stereochemical Analysis of Isopentenyl Diphosphate Isomerase Type II from <i>Staphylococcus </i><i>a</i><i>ureus</i> Using Chemically Synthesized (<i>S</i>)- and (<i>R</i>)-[2-<sup>2</sup>H]Isopentenyl Diphosphates
作者:Chai-lin Kao、William Kittleman、Hua Zhang、Haruo Seto、Hung-wen Liu
DOI:10.1021/ol0524050
日期:2005.12.1
the catalysis of isopentenyl diphosphate (IPP) isomerase type II from Staphylococcus aureus, which is a flavoprotein catalyzing the interconversion of IPP and dimethylallyl diphosphate, we have chemically synthesized (S)- and (R)-[2-2H]IPP and carried out stereochemical analysis of the reaction. Our results show that the C-2 deprotonation of IPP by this enzyme is pro-R stereospecific, suggesting a similar
The Development of Cyclic Sulfolanes as Novel and High-Affinity P2 Ligands for HIV-1 Protease Inhibitors
作者:Arun K. Ghosh、Hee Yoon Lee、Wayne J. Thompson、Chris Culberson、M. Katharine Holloway、Sean P. McKee、Peter M. Munson、Tien T. Duong、Anthony M. Smith
DOI:10.1021/jm00034a016
日期:1994.4
synthesis of a novel series of proteaseinhibitors incorporating conformationally constrained cyclicligands for the S2-substrate binding site of HIV-1protease is described. We recently reported urethanes of 3-tetrahydrofuranyl as P2ligands for HIV-1proteaseinhibitors. Subsequently, we have found that the urethane of 3(S)-hydroxysulfolane further increased the in vitro potency of these inhibitors. Furthermore