First total synthesis and structure confirmation of diacetylenic polyol (+)-oploxyne B
摘要:
The first total synthesis of the natural product (+)-oploxyne B is achieved. The synthesis has led to the confirmation of absolute stereochemistry of the natural product. The natural product displayed cytotoxic activity with IC50 values varying from 16 to 53 mu M in four cancer cell lines tested. (C) 2013 Elsevier Ltd. All rights reserved.
Stereoselective Rh-Catalyzed Hydrogenative Desymmetrization of Achiral Substituted 1,4-Dienes
作者:Héctor Fernández-Pérez、Joan R. Lao、Anton Vidal-Ferran
DOI:10.1021/acs.orglett.6b01088
日期:2016.6.17
Highly efficient catalytic stereoselective hydrogenative desymmetrization reactions mediated by rhodiumcomplexes derived from enantiopure phosphine–phosphite (P–OP) ligands are described. The highest performing ligand, which contains a TADDOL-derived phosphite fragment [TADDOL = (2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(diphenylmethanol)], presented excellent catalytic properties for the desymmetrization
A concise total synthesis of enantiomerically pure (+)-cis- and (+)-trans-lauthisan
作者:Leo A. Paquette、Thomas J. Sweeney
DOI:10.1021/jo00293a006
日期:1990.3
Stereoselectivity in the Rhodium-Catalysed Reductions of Non-Conjugated Dienes
作者:Bao Nguyen、John M. Brown
DOI:10.1002/adsc.200900013
日期:2009.6
Abstractmagnified imageThe stereochemical course of rhodium‐catalysed addition of hydrogen and catecholborane to bicyclo[2.2.1]heptadiene, and of hydrogen to a range of cyclic dienes has been analysed. For hydroboration, the overall catalytic reaction possesses exo‐selectivity, but the initial step is endo‐selective. For hydrogenation (deuteration), the first step may occur with either exo‐ or endo‐ selectivity, depending on the structure of the diene. This enables a distinction to be made between pathways involving prior dissociation of the diene, and direct addition to the complexed diene without full dissociation. The relative ease of hydrogenation of the first and second double bonds varies markedly with reactant structure, and also depends on the choice of catalyst ligands. For dicyclopentadiene, hydrogenation of the cyclopentene double bond is accompanied by rapid alkene isomerisation, as revealed by deuterium addition. The asymmetric hydrogenation of acyclic skipped meso‐dienes is reported, demonstrating control of relative rates of the two sequential steps, with ees of up to 53% after the first reduction.
Hayashi, Masahiko; Kaneko, Toshiyuki; Oguni, Nobuki, Journal of the Chemical Society. Perkin transactions I, 1991, # 1, p. 25 - 28
Directing effects of tethered alkenes in nickel-catalyzed coupling reactions of 1,6-enynes and aldehydes
作者:Ryan M. Moslin、Karen M. Miller、Timothy F. Jamison
DOI:10.1016/j.tet.2006.03.122
日期:2006.8
Nickel-catalyzed reductive coupling reactions of aldehydes and 1,6-enynes proceed in excellent regioselectivity in the absence of a phosphine, and the use of a monodentate phosphine additive leads to the formation of the opposite regioisomer with equally high selectivity. Both products are the result of the same fundamental mechanism, with the inversion of regioselectivity being the result of stereospecific ligand substitution at the metal center. (c) 2006 Elsevier Ltd. All rights reserved.