71687-03-1Relevant articles and documents
A one-pot synthesis of (E)-disubstituted alkenes by a bimetallic [Rh-Pd]-catalyzed hydrosilylation/hiyama cross-coupling sequence
Thiot, Carine,Schmutz, Marc,Wagner, Alain,Mioskowski, Charles
, p. 8971 - 8978 (2007)
A bimetallic [Rh-Pd] catalyst was prepared by soaking into an iodide ionic gel an equimolar solution of [RhCl(PPh3)3] and Pd(OAc)2 in CH2Cl2. Its catalytic activity was evaluated by rhodium-catalyzed hydrosilylation (H), palladium-catalyzed Hiyama coupling (C), and in the one-pot hydrosilylation/Hiyama coupling sequence (H/C). It was found that the homogeneous combination [RhCl(PPh3) 3]/NaI was a superior system compared to the polyionic mono- and bimetallic rhodium catalysts in the hydrosilylation of terminal alkynes. Interestingly, the most effective catalyst in terms of stereo- and chemoselectivities was observed to be the bimetallic ionic gel [Rh-Pd] in the one-pot process leading to (E)-alkenes with good yields. The remarkable stereocontrol is ascribed to a beneficial Pd-catalyzed isomerization from the mixture of stereoisomeric vinylsilanes obtained in the initial hydrosilylation step into the more stable (E)-adduct. The [Rh-Pd] heterogeneous catalyst also showed a higher chemoselectivity than the homogeneous catalytic combination, and no detrimental formation of Sonogashira side product was observed due to an ionic-gel-mediated kinetic modulation. To illustrate its scope and limitations, the described one-pot bimetallic catalytic sequence was extended to functionalized terminal alkynes and various iodide substrates. Conjugated systems, such as hydroxycinnamaldehyde, dienes, and trienes, were synthesized in good overall yields. To avoid deactivation of the Rh species, N-heterocyclic iodides had to be added sequentially after completion of hydrosilylation.
Peptide-catalyzed regio- and enantioselective reduction of α,β,γ,δ-unsaturated aldehydes
Akagawa, Kengo,Sen, Jun,Kudo, Kazuaki
supporting information, p. 11585 - 11588 (2013/11/06)
A resin-supported peptide catalyst (see box in the scheme) was used in the title reaction. The inherent regioselectivity was overcome by the peptide catalyst to promote the 1,6-selective reaction prior to 1,4-reduction. High stereoconvergence was also achieved when using a mixture of geometric isomers of the starting aldehydes. Ach=1-amino-1-cyclohexanecarboxylic acid. Copyright
A cross-metathesis approach to the synthesis of new etretinate type retinoids, ethyl retinoate and its 9Z-isomer
Maj, Jadwiga,Morzycki, Jacek W.,Rárová, Lucie,Wasilewski, Grzegorz,Wojtkielewicz, Agnieszka
supporting information, p. 5430 - 5433 (2012/11/07)
Two aromatic retinoids were synthesized from styrene derivatives using a novel strategy with a cross-metathesis reaction as a key step. The biological activity of the new etretinate analogues was tested. Cross-metathesis reactions were also employed for the preparation of ethyl retinoate and its 9Z-isomer via the C15 + C5 route.
Photocurrents of solar cells sensitized by aggregate-forming polyenes: Enhancement due to suppression of singlet-triplet annihilation by lowering of dye concentration or light intensity
Wang, Xiao-Feng,Koyama, Yasushi,Nagae, Hiroyoshi,Yamano, Yumiko,Ito, Masayoshi,Wada, Yuji
, p. 309 - 315 (2008/02/12)
Titania-based Gr?tzel-type solar cells were fabricated by the use of polyene dyes with various transition dipole moments. In the dye having the largest transition dipole among the samples, an aggregate was readily formed through dispersive interaction, an
