2699-89-0Relevant academic research and scientific papers
Ligand-Controlled Regiodivergence in the Copper-Catalyzed [2,3]- and [1,2]-Rearrangements of Iodonium Ylides
Xu, Bin,Tambar, Uttam K.
supporting information, p. 12073 - 12076 (2016/09/28)
Despite the importance of allylic ylide rearrangements for the synthesis of complex molecules, the catalyst control of [2,3]- and [1,2]-rearrangements remains an unsolved problem. We developed the first regiodivergent [2,3]- and [1,2]-rearrangements of iodonium ylides that are controlled by copper catalysts bearing different ligands. In the presence of a 2,2′-dipyridyl ligand, diazoesters and allylic iodides react via a [2,3]-rearrangement pathway. Alternatively, a phosphine ligand favors the formation of the [1,2]-rearrangement product. A series of α-iodoesters containing a broad range of functional groups were obtained in high yields, regioselectivities, and diastereoselectivities. Deuterium-labeling studies suggest distinct mechanisms for the regioselective rearrangements.
Chemo-, regio-, and stereoselective Heck-Matsuda arylation of allylic alcohols under mild conditions
Chaudhari, Tohasib Yusub,Hossian, Asik,Manna, Manash Kumar,Jana, Ranjan
supporting information, p. 4841 - 4845 (2015/05/05)
Heck arylation with allylic alcohol is extremely challenging due to chemo-, regio-, and stereoselective scrambling. Here we report a mild protocol for the alcohol selective β- and α-arylation of allylic and cinnamyl alcohols respectively with aryldiazonium salts. The steric and electronic parameters of the alkene play a prominent role in the regioselectivity.
Catalytic asymmetric bromoetherification and desymmetrization of olefinic 1,3-diols with C2-symmetric sulfides
Ke, Zhihai,Tan, Chong Kiat,Chen, Feng,Yeung, Ying-Yeung
supporting information, p. 5627 - 5630 (2014/05/06)
An enantioselective and highly diastereoselective bromoetherification and desymmetrization of olefinic 1,3-diols has been developed using a C 2-symmetric cyclic sulfide catalyst. This methodology has been successfully applied to the synthesis of the key intermediate of an orally active antifungal drug posaconazole (Noxafil).
Enantioselective one-pot catalytic synthesis of 4,5-epoxy-3-alkanols and 1-Phenyl-2,3-epoxy-1-alkanols from α,β-unsaturated aldehydes
Infante, Rebeca,Hernandez, Yulan,Nieto, Javier,Andres, Celia
, p. 4863 - 4869 (2013/08/23)
Conformationally restricted perhydrobenzoxazines have been demonstrated to be good chiral ligands for one-pot asymmetric ethylation/epoxidation, and the unprecedented arylation/epoxidation of trisubstituted α,β-unsaturated aldehydes. The scope of the reaction has been studied and a wide set of substrates with allylic strain of different nature has been explored, obtaining good or total diastereoselectivities in all cases. The enantiocontrol was good or high for the ethylation/epoxidation reaction, whereas it remained at moderate or good levels for the arylation/epoxidation. The reaction is general for trisubstituted enals, and alkylic and aromatic substituents are tolerated at both the α- and β-position of the unsaturated aldehyde; however, disubstituted enals remain challenging substrates. When the one-pot and two-pot protocols were compared, no significant differences concerning the stereocontrol were found, so the advantages of the one-pot procedure are clear. Copyright
Addition of arylboronic acids to arylpropargyl alcohols en route to indenes and quinolines
Panteleev, Jane,Huang, Richard Y.,Lui, Erica K. J.,Lautens, Mark
supporting information; experimental part, p. 5314 - 5317 (2011/12/01)
A regio- and stereoselective rhodium-catalyzed synthesis of trisubstituted allylic alcohols is described. The utility of these synthons is demonstrated in a convenient synthesis of indenes and quinolines.
Exploratory studies on the reaction between iodoarenes and acetylenes: One-pot, Pd-[Bmim][BF4] catalyzed preparation of trianisylethylene
Barros, Jose C.,Souza, Andrea L. F.,Da Silva, Joaquim F. M.,Antunes
scheme or table, p. 549 - 553 (2012/01/13)
The reaction between iodoarenes and acetylenes mediated by palladium was studied, showing selectivity changes based on the nature of the substituent. A new, phosphine-, copper-, and amine-free methodology was developed, in which the synthesis of trianisylethylene from 4-iodoanisole and trimethylsilylacetylene was promoted presumably by an N-heterocyclic-carbene derived from an ionic liquid and a palladium salt, using ethanol as the hydrogen source. Graphical Abstract: [Figure not available: see fulltext.]
Palladium-catalyzed Heck arylations of allyl alcohols in ionic liquids: Remarkable base effect on the selectivity
Calo, Vincenzo,Nacci, Angelo,Monopoli, Antonio,Ferola, Valentina
, p. 2596 - 2601 (2007/10/03)
Pd-catalyzed Heck arylation of allyl alcohols in tetraalkylammonium ionic liquids (ILs) can be made highly selective toward the formation of either aromatic carbonyl compounds or aromatic conjugated alcohols by carefully choosing both the IL and the base.
Development and application of a direct vinyl lithiation of cis-stilbene and a directed vinyl lithiation of an unsymmetrical cis-stilbene
Cotter, Juliet,Hogan, Anne-Marie L.,O'Shea, Donal F.
, p. 1493 - 1496 (2008/02/02)
Equation Presented The vinyl deprotonation of cis-stilbene can be readily achieved using s-BuLi in THF at -25°C. The generated 1-lithio-1,2- diphenylethene undergoes an in situ Z-to-E isomerization, and subsequent reaction with electrophiles results in an efficient stereoselective synthesis of trisubstituted alkenes. A directed vinyl lithiation of the unsymmetrical cis-stilbene 2-styryl-phenyl-carbamic acid tert-butyl ester can be achieved regioselectively, thereby expanding this methodology for further synthetic applications in indole chemistry.
The epoxy-Ramberg-Baecklund reaction (ERBR): A sulfone-based method for the synthesis of allylic alcohols
Evans, Paul,Johnson, Paul,Taylor, Richard J. K.
, p. 1740 - 1754 (2007/10/03)
The epoxy-Ramberg-Baecklund reaction (ERBR) is outlined, in which α,β-epoxy sulfones are converted into a range of mono-, di- and tri-substituted allylic alcohols, on treatment with base. Modification of this method enabled the preparation of enantio-enriched allylic alcohols following the diastereoselective epoxidation of enantio-enriched vinyl sulfones that were accessed efficiently from the chiral pool. The scope, optimisation and limitations of the ERBR as a method for the preparation of allylic alcohols are discussed. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Highly regio- and stereoselective halohydroxylation reaction of 1,2-allenyl phenyl sulfoxides. Reaction scope, mechanism, and the corresponding Pd- or Ni-catalyzed selective coupling reactions
Ma, Shengming,Ren, Hongjun,Wei, Qi
, p. 4817 - 4830 (2007/10/03)
A highly regio- and stereoselective halohydroxylation of 1,2-allenyl sulfoxides with X+ and water was developed. The reaction shows E-stereoselectivity. In the iodohydroxylation reaction, I2 was used to introduce the iodine atom. For
