32316-90-8Relevant articles and documents
Palladium-Catalyzed Suzuki Reactions in Water with No Added Ligand: Effects of Reaction Scale, Temperature, pH of Aqueous Phase, and Substrate Structure
Li, Zhao,Gelbaum, Carol,Heaner, William L.,Fisk, Jason,Jaganathan, Arvind,Holden, Bruce,Pollet, Pamela,Liotta, Charles L.
, p. 1489 - 1499 (2016/08/30)
The heterogeneous palladium-catalyzed Suzuki reactions between model aryl bromides (4-bromoanisole, 4-bromoaniline, 4-amino-2-bromopyridine, and 2-bromopyridine) and phenylboronic acid have been successfully conducted in water with no added ligand at the 100 mL scale using 20-40 mmol of aryl bromide. The product yields associated with these substrates were optimized, and key reaction parameters affecting the yields were identified. The results clearly indicate that the reaction parameters necessary to achieve high yields are substrate-dependent. In addition, it is demonstrated that aqueous Suzuki reactions of substrates containing basic nitrogen centers can produce quantitative yields of desired products in the absence of added ligand.
Pd/mannose promoted tandem cross coupling-nitro reduction: Expedient synthesis of aminobiphenyls and aminostilbenes
Rohilla, Sandeep,Pant, Pradeep,Jain, Nidhi
, p. 31311 - 31317 (2015/04/22)
The dual role of d-mannose as a ligand for Pd catalyzed cross-coupling, and as a hydrogen source for nitro reduction is demonstrated in a modular cross coupling-nitro reduction sequence. The synthetic utility and generality of this green protocol has been illustrated by the synthesis of 20 aminobiphenyl and 10 aminostilbene derivatives in high yields through a one-pot Suzuki coupling-nitro reduction and a Heck coupling-nitro reduction, respectively, starting from halonitroarenes as substrates.
NOVEL CATALYSTS
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Page/Page column 62, (2012/06/01)
The present invention provides novel compounds and ligands that are useful in transition metal catalyzed cross-coupling reactions. For example, the compounds and ligands of the present invention are useful in palladium or gold catalyzed cross-coupling reactions.
Models for intramolecular exchange in organic π-conjugated open-shell systems: A comparison of three non-kekule biphenyldinitrenes
Minato, Masaki,Lahti, Paul M.,Van Willigen, Hans
, p. 4532 - 4539 (2007/10/02)
The important effect of connectivity upon the nature of intramolecular exchange coupling of unpaired electrons by the biphenyl group was investigated by cryogenic matrix photolysis of diazide precursors expected to yield biphenyl-3,4′-dinitrene (1), biphenyl-3,3′-dinitrene (2), and biphenyl-4,4′-dinitrene (3). System 1 was predicted by parity-based qualitative models to exhibit a high-spin ground state. By Curie law analysis of its electron spin resonance (ESR) spectrum at cryogenic temperatures in frozen 2-methyltetrahydrofuran solution, 1 was found to be a quintet ground-state dinitrene with zero field splitting (zfs) parameters of |D/hc| = 0.153 cm-1, |E/hc| = 0.003 cm-1. System 2 was predicted to be disjoint with nearly-degenerate high-spin and low-spin states. Cryogenic frozen solution ESR spectroscopy showed no ESR-active dinitrene 2 upon extended photolysis of its appropriate diazide precursor, although the related mononitrene with zfs of |D/hc| = 0.996 cm-1 was clearly visible. We presume that system 2 was produced in this experiment, but that it acts either as a singlet ground-state dinitrene or as a pair of isolated mononitrenes. A biradical ESR spectrum was found for photolysis of the diazide precursor to 3, with zfs of |D/hc| = 0.189 cm-1 and |E/hc| -1. The thermal dependence of this biradical spectrum shows it to be an excited state, consistent with quinonoidal dinitrene 3 having a singlet ground state and a triplet excited state ca. 0.6 kcal/mol higher in energy. The results for dinitrenes 1-3 were compared to related work on dicarbene molecules described by others, and it was found that the dinitrenes and dicarbenes exhibit similar electron exchange coupling behavior.
