18986-14-6Relevant articles and documents
Enantioselective Cu(I)-Catalyzed Cycloaddition of Prochiral Diazides with Terminal or 1-Iodoalkynes
Wang, Cai,Zhu, Ren-Yi,Liao, Kui,Zhou, Feng,Zhou, Jian
supporting information, p. 1270 - 1274 (2020/02/13)
We report an unprecedented highly enantioselective desymmetric Cu(I)-catalyzed 1,3-dipolar cycloaddition of diazides with terminal alkynes and 1-iodoalkynes, affording tertiary alcohols bearing a 1,2,3-triazole moiety in high yield and excellent ee value. PYBOX ligands with a C4 shielding group once again show the promising ability to achieve higher enantioselectivity.
Implementing liquid-crystalline properties in single-stranded dinuclear lanthanide helicates
Terazzi, Emmanuel,Zaim, Amir,Bocquet, Bernard,Varin, Johan,Guenee, Laure,Dutronc, Thibault,Lemonnier, Jean-Francois,Floquet, Sebastien,Cadot, Emmanuel,Heinrich, Benoit,Donnio, Bertrand,Piguet, Claude
, p. 3323 - 3333 (2013/07/26)
The connection of flexible protodendritic wedges to the bis-tridentate rigid polyaromatic ligand L1 provides amphiphilic receptors L5 and L6; their reduced affinities for complexing trivalent lanthanides (Ln = La, Y, Lu) in organic solvent (by fifteen orders of magnitude!) prevent the formation of the expected dinuclear triple-stranded helicates [Ln2(Lk) 3]6+. This limitation could be turned into an advantage because L1 or L6 can be treated with [Ln(hfac)3] (Hhfac = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione) to give neutral single-stranded [Ln2(Lk)(hfac)6] complexes with no trace of higher-order helicates. Whereas ligands L1 and L5 are not liquid crystals, L6 can be melted above room temperature (41°C) to give a nematic mesophase, and its associated dinuclear helical complex [Y2(L6)(hfac)6] self-organises at the same temperature into a fluidic smectic mesophase. The lipophilic dendritic ligand L6 selectively reacts with trivalent yttrium hexafluoroacetylacetonate (hfac) to give the liquid-crystalline single-stranded dinuclear helicate [Y2(L6)(hfac)6], which self-organises into an SmA mesophase. Copyright
Supporting multiple organometallic catalysts on poly(norbornene) for cyanide addition to α,β-unsaturated imides
Madhavan, Nandita,Sommer, William,Weck, Marcus
experimental part, p. 1 - 7 (2011/03/16)
A two-catalyst system comprising of salen(AlCl) and pybox(ErCl3) complexes supported onto poly(norbornene) has been developed. As a proof of concept the activity of the two-catalyst system was gauged for the addition of cyanide to α,β-unsaturated imides which has been shown to follow a bimetallic mechanism. The activity of the supported two-catalyst system was significantly higher than catalytic systems derived from mixtures of the two catalysts. In addition, the co-polymer could be readily recovered and reused up to 3 cycles without significant loss in conversions and yields. Nevertheless, a decrease in enantioselectivity of the cyanide adduct was observed with each subsequent cycle indicating some loss in catalytic selectivity. The reported strategy opens up avenues for supporting multiple catalysts on the same polymer backbone for catalyst-based one-pot cascade reactions.
