203316-75-0Relevant academic research and scientific papers
Self-assembled poly(imidazole-palladium): Highly active, reusable catalyst at parts per million to parts per billion levels
Yamada, Yoichi M. A.,Sarkar, Shaheen M.,Uozumi, Yasuhiro
supporting information; experimental part, p. 3190 - 3198 (2012/04/10)
Metalloenzymes are essential proteins with vital activity that promote high-efficiency enzymatic reactions. To ensure catalytic activity, stability, and reusability for safe, nontoxic, sustainable chemistry, and green organic synthesis, it is important to develop metalloenzyme-inspired polymer-supported metal catalysts. Here, we present a highly active, reusable, self-assembled catalyst of poly(imidazole-acrylamide) and palladium species inspired by metalloenzymes and apply our convolution methodology to the preparation of polymeric metal catalysts. Thus, a metalloenzyme-inspired polymeric imidazole Pd catalyst (MEPI-Pd) was readily prepared by the coordinative convolution of (NH4)2PdCl4 and poly[(N-vinylimidazole)-co-(N- isopropylacrylamide)5] in a methanol-water solution at 80 °C for 30 min. SEM observation revealed that MEPI-Pd has a globular-aggregated, self-assembled structure. TEM observation and XPS and EDX analyses indicated that PdCl2 and Pd(0) nanoparticles were uniformly dispersed in MEPI-Pd. MEPI-Pd was utilized for the allylic arylation/alkenylation/vinylation of allylic esters and carbonates with aryl/alkenylboronic acids, vinylboronic acid esters, and tetraaryl borates. Even 0.8-40 mol ppm Pd of MEPI-Pd efficiently promoted allylic arylation/alkenylation/vinylation in alcohol and/or water with a catalytic turnover number (TON) of 20 000-1 250 000. Furthermore, MEPI-Pd efficiently promoted the Suzuki-Miyaura reaction of a variety of inactivated aryl chlorides as well as aryl bromides and iodides in water with a TON of up to 3 570 000. MEPI-Pd was reused for the allylic arylation and Suzuki-Miyaura reaction of an aryl chloride without loss of catalytic activity.
A highly active and reusable self-assembled poly(imidazole/palladium) catalyst: Allylic arylation/alkenylation
Sarkar, Shaheen M.,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
supporting information; experimental part, p. 9437 - 9441 (2011/11/06)
Gobs of globules: A polymeric imidazole/acrylamide palladium catalyst, MPPI-Pd (M=PdIICl and Pd0), was utilized for the allylic arylation/alkenylation of allylic esters with aryl/alkenylboronic acids and tetraaryl borates. Low catalyst loadings efficiently promoted the reaction with a catalytic turnover number of 20000-1250000. The catalyst can be reused without loss of catalytic activity.
Integrated chemical process. Construction of highly substituted allylic moieties from allylic sulfones in one-pot
Orita, Akihiro,Watanabe, Akihiro,Tsuchiya, Hiroshi,Otera, Junzo
, p. 2889 - 2898 (2007/10/03)
According to 'integrated chemical process', a novel one-pot process for construction of highly substituted allylic moieties has been achieved. A series of alkylation of allylic sulfones and palladium-catalyzed reductive desulfonylation by use of LiBHEt3 is integrated. The double alkylation furnishes more substituted olefins. Use of arylzinc compounds in place of the hydride enables electrophilic alkylation/nucleophilic arylation in one-pot. The integrated process provides higher overall yields than the corresponding stepwise process.
Phosphine-directed stereo- and regioselective Ni-catalyzed reactions of Grignard reagents with allylic ethers
Didiuk, Mary T.,Morken, James P.,Hoveyda, Amir H.
, p. 1117 - 1130 (2007/10/03)
Studies on the directed regio- and stereoselective Ni-catalyzed allylic substitution reactions involving methyl-and phenylmagnesium bromides and various acyclic and cyclic allylic ethers are reported. In the presence of a properly positioned internal Lewis base, C-C bonds can be formed catalytically and with excellent levels of selectivity. Internal chelation allows Ni-catalyzed C-C bond forming reactions that are otherwise non-selective, sluggish, or do not occur at all, to proceed to completion readily, in excellent yields, at ambient temperature and with high regio- and stereocontrol. Directed alkene isomerization highlights an especially attractive feature of the metal-catalyzed alkylation strategy: because the initial product contains a prostereogenic site that remains within reach of the internal Lewis base, it can be subjected to additional directed stereoselective manipulations.
