Smaller, faster, better: modular synthesis of unsymmetrical ammonium salt-tagged NHC–gold(<scp>i</scp>) complexes and their application as recyclable catalysts in water
作者:Katrin Belger、Norbert Krause
DOI:10.1039/c5ob01286d
日期:——
Facile access towards a small library of unsymmetrical ammonium salt-tagged N-heterocyclic carbene gold(I) complexes is described, and their application as recyclable catalysts in cyclization reactions of acetylenic carboxylic acids and amides to lactones and lactams, respectively, in aqueous media is demonstrated. Catalyst 1ab was applied in the synthesis of 2-epi-clausemarine A (16).
Bismuth-catalyzed Intramolecular Hydro-oxycarbonylation of Alkynes
作者:Kimihiro Komeyama、Keita Takahashi、Ken Takaki
DOI:10.1246/cl.2008.602
日期:2008.6.5
Bi(OTf)3 was found to be a good catalyst for intramolecular addition of carboxylic acids to alkynes (hydro-oxycarbonylation), which afforded the corresponding 5- and 6-membered lactones in moderate...
Synthesis and photophysical characterization of bacteriochlorins equipped with integral swallowtail substituents
作者:Yizhou Liu、Srinivasarao Allu、Muthyala Nagarjuna Reddy、Don Hood、James R. Diers、David F. Bocian、Dewey Holten、Jonathan S. Lindsey
DOI:10.1039/c7nj00499k
日期:——
three intermediates were determined. Bacteriochlorins synthesized herein exhibit characteristic bacteriochlorophyll-like absorption spectra, including a Qy band in the region of 730–758 nm. The swallowtail groups have little impact on the excited-state properties of the bacteriochlorins, and the slight changes of spectral properties that are observed stem from substituent electronic effects rather than
Effector Regulated Catalytic Cyclization of Alkynoic Acids Using Pt
<sub>2</sub>
L
<sub>4</sub>
Cages
作者:Eduard O. Bobylev、Julian Ruijter、David A. Poole、Simon Mathew、Bas de Bruin、Joost N. H. Reek
DOI:10.1002/anie.202218162
日期:——
Pt2L4 cages are found to catalyze the cyclization of alkynoicacids. The reaction rates are depending on effector guests bound in the cage, leading to an enhancement of the catalytic rate by up to 19-fold or a decrease by 5-fold. In contrast to this effector-controlled rate enhancement using the binding pocket of Pt2L4, the molecular analogue PtL4 displays no significant changes in catalytic rate.
Pt 2 L 4笼被发现催化炔酸的环化。反应速率取决于笼中结合的效应客体,导致催化速率提高多达 19 倍或降低 5 倍。与使用 Pt 2 L 4结合袋的效应子控制速率增强相比,分子类似物 PtL 4的催化速率没有显着变化。通过效应器诱导笼催化反应的速率变化,意想不到的新反应性和复杂的自动调节出现在眼前。