68269-56-7Relevant academic research and scientific papers
Formation of quaternary stereogenic centers by copper-catalyzed asymmetric conjugate addition reactions of alkenylaluminums to trisubstituted enones
Mueller, Daniel,Alexakis, Alexandre
supporting information, p. 15226 - 15239 (2013/11/06)
Alkenylaluminums undergo asymmetric copper-catalyzed conjugate addition (ACA) to β-substituted enones allowing the formation of stereogenic all-carbon quaternary centers. Phosphinamine-copper complexes proved to be particularly active and selective compared with phosphoramidite ligands. After extensive optimization, high enantioselectivities (up to 96 % ee) were obtained for the addition of alkenylalanes to β-substituted enones. Two strategies for the generation of the requisite alkenylaluminums were explored allowing for the introduction of aryl- and alkyl-substituted alkenyl nucleophiles. Moreover, alkyl-substituted phosphinamine (SimplePhos) ligands were identified for the first time as highly efficient ligands for the Cu-catalyzed ACA. Chiral synthesis made easy: The copper-catalyzed conjugate addition of alkenylaluminum reagents to 3-substituted cyclic enones allows for the formation of all-carbon chiral quaternary centers (see scheme; CuTC=copper(I) thiophene-2-carboxylate). Chiral phosphinamine (SimplePhos) ligands were found to be highly efficient for this transformation.
Creation of highly congested quaternary centers via Cu-catalyzed conjugate addition of alkenyl alanates to β-substituted cyclic enones
Mueller, Daniel,Alexakis, Alexandre
supporting information, p. 1594 - 1597 (2013/07/05)
Easily prepared alkenylalanates proved to be excellent nucleophiles for the creation of highly congested quaternary centers via copper-catalyzed conjugate addition. In addition, functionalized cis-decaline systems can now be prepared in a simple two-step sequence involving Cu-catalyzed conjugate addition with functionalized alkenylalanates.
Total synthesis of hapalindoles J and U
Rafferty, Ryan J.,Williams, Robert M.
, p. 519 - 524 (2012/03/26)
The total synthesis of d,l-hapalindoles J and U has been accomplished. Hapalindole J was prepared in 11% overall yield over 11 synthetic steps and hapalindole U was prepared in 25% overall yield over 13 synthetic steps from commercially available materials. The route employs a novel silyl ether-based strategy for accessing the 6:5:6:6 ring system of the hapalindoles rapidly and in good yields.
Intramolecular azide-alkene 1,3-dipolar cycloaddition/enamine addition(s) cascade reaction: Synthesis of nitrogen-containing heterocycles
De Miguel, Irene,Herradon, Bernardo,Mann, Enrique
supporting information; experimental part, p. 1731 - 1736 (2012/07/28)
A cascade intramolecular azide-alkene 1,3-dipolar cycloaddition/1,2 enamine and/or 1,4 enamine addition reaction sequence has been developed, and provides access to a variety of nitrogen containing heterocycles from readily available ω-azido alkenes. Copy
Asymmetric synthesis of 6′-hydroxyarenarol: The proposed biosynthetic precursor to popolohuanone E
Munday, Rachel H.,Denton, Ross M.,Anderson, James C.
, p. 8033 - 8038 (2008/12/22)
(Chemical Equation Presented) The first synthesis of (+)-6′- hydroxyarenarol 3, the proposed biogenetic precursor to popolohuanone E (1), is described. An enantioselective route to key iodide intermediate 12 has been developed allowing the asymmetric synt
Studies Directed toward the Total Synthesis of Cerorubenic Acid-III. 1. Expedient Construction of the Tetracyclic Core by Oxyanionic Sigmatropy
Paquette, Leo A.,Poupart, Marc-Andre
, p. 4245 - 4253 (2007/10/02)
A synthesis of the ABCD ring framework of cerorubenic acid-III is described.Diketone 5 was first prepared by intramolecular oxidative coupling of the dienolate 10 and then suitably desymmetrized to deliver 15b.Anionic oxy-Cope rearrangement of this intermediate resulted in construction of 18, a ketone not only having all three contiguous stereogenic centers properly established but also equipped with adequate functionality for the further elaboration of ring D.In the present effort, this thrust took the form of homologation to 21, conversion to the activated diene 22, and Diels-Alder cycloaddition to methyl acrylate at high pressure.Once it became obvious that first-formed ketone 26 greatly preferred adoption of trans stereochemistry at the ring juncture, attempts to skirt this issue were made by preparing both 29 and 32.However, these advanced intermediates proved unresponsive to conjugate reduction, and attention was therefore redirected to alternative possible means for elaboration of the eastern sector.
EFFECT OF GEGENIONS ON ORGANOCUPRATE REACTIVITY/SELECTIVITY: HIGHER ORDER, MIXED LITHIO-SODIO CYANOCUPRATES
Lipshutz, Bruce H.,Ellsworth, Edmund L.,Behling, James R.,Campbell, Arthur L.
, p. 893 - 896 (2007/10/02)
Several different types of reactions characteristic of organocuprates have been studied using reagents RTRRCu(CN)LiNa derived from CuCN and one equivalent each of an organolithium (RTLi) and organosodium (RRNa) species.
