Triphenylphosphine PPh

Wittig olefination of 2-nitro-Z-cinnamaldehyde (1300) with the phosphonium bromide 1301 led to the diene 1302. The Diels-Alder cycloaddition of 1302 with maleimide (1303), followed by dehydrogenation with DDQ, afforded the phthali-mide 1304. Double deoxygenation of 1304 with triphenylphosphine (PPhs) in collidine gave O-methylarcyiiaflavin B (1305). Finally, heating of 1305 with molten pyridine hydrochloride led to arcyriaflavin B (346) (759) (Scheme 5.215). 

Some other common ligands are pyridine (py), ethylenediamine (en), cyanide ion (CN ), thiocyanate ion (SCN, acetylacetonate (acac), sahcy-laldehyde (sal), triphenylphosphine (PPhs) and various trihalophosphines. Ethylenediame and acetylacetonate are examples of two common bidentate hgands. 

Cobalt and triphenylphosphine (PPhs) ligands are commonly encountered in homogeneous catalyzed processes. Therefore, dichlorobis(triphenylphosphine)cobalt(II) has been selected as a homogeneous model catalyst. In 1-butanol, this complex is in equilibrium with the free Co(II)Q2 and PPh3 ligands. 

The catalysts were cationic palladium-phosphine systems prepared from palladium acetate, an excess of triphenylphosphine (PPhs) and a Bronsted acid of a weakly or noncoordinating anion (e. g., p-tosylate (OTs ) methanol was used as both the solvent and a reactant. An unexpected change in selectivity was observed upon replacement of the excess of PPhs by a stoichiometric amount of the bidentate l,3-bis(diphenylphosphino)propane (dppp). Under the same conditions. 

Triphenylcarbinol (PhsCOH), 281 Triphenylmethyl carbocation, 106, 146, 281 Triphenylphosphine (PPhs)... 

An organobase including guanidine is often used as co-catalyst (or base) in palladium coupling reactions [84]. The 2-methylenepropane-l,3-diol diacetate reacts with 7,8-dihydroquinoline derivative in the presence of palladium acetate [Pd(OAc)2], TMG (1) and triphenylphosphine (PPhs) to give the methylene bridged compound in 92% yield, which can be converted to a diamino analogue of huperzine A, an inhibitor of acetylcholine esterase [84a](Scheme 4.32). 

The C-2 hydroxyl derivative with the unnatural configuration (2-Epi-57 or 62) was synthesized using Mitsunobu conditions of triphenylphosphine (PPhs), diisopropyl azodicarboxylate (DIAD), and 4-nitrobenzoic acid as the nucleophile, which was subsequently hydrolyzed with K2CO3 in MeOH to afford 62 in 64% yield over two steps [34]. Compounds 57 and 2-epi-57 have been exploited as common intermediates in diversification of the C-2 position. Hydroxyl 57 has been utilized... 

Several reagents and reaction conditions such as TMSI (generated in situ from TMSCl and Nal), magnesium nitride (Mg3N2), triphenylphosphine (PPhs), thiamine hydrochloride (vitamin mnding under solvent-free conditions, PTSA with ultrasonic irradiation were recently reported to mediate efficiently the Hantzsch dihydropyridine synthesis. For instance, 1,4-dihydropyridines 143 were obtained in good yields using thiamine hydrochloride (vitamin B ) as the catalyst under solvent-free conditions at room temperature. ... 

A 2-1, four necked, dried round bottomed flask equiped with a 500 ml addition funnel, mechanical stirrer, thermometer, and stopcock adapter was charged with Zn-powder (131.00 g, 2.0 mol), sodium bromide (15.00 g, 0.15 mol), triphenylphosphine (PPhs, 131.00 g, 0.5 mol) and anhydrous nickel(ll) chloride (6.50 g, 0.05 mol). The reaction flask was evacuated and filled with nitrogen several times. Nitrogen was then swept... 

In 2005, Nikaido et al. [9] reported the first example of cobalt-phosphine-catalyzed intermolecular Diels-Alder dimerization reaction (Scheme 16.7). The dimerization of piperine derivative (28) in the presence of cobalt-phosphine complexes appear to be more efficient than that of using only cobalt, which, combined with the result under purely thermal conditions, indicates that the addition of phosphine ligand changes the inhibition of cobalt to the reaction into promotion. Triphenylphosphine (PPhs) is the most favorable phosphine ligand of the reaction. 

Ligands triphenylphosphine (PPhs), - bis(diphenylphosphino)-methane (dppm), (/n-sulfonatophenyl)diphenylphosphine (TPPMS) and 1,5-cyclooctadiene (COD). 

For monolithic disk synthesis, solutions of NBE, DMN-H6, and tris(norborn-5-ene-2-ylmethylenoxy)methylsilane, respectively, in 2-propanol and toluene (25 25 41 9, all wt.%) were subject to ROMP using the first-generation Gmbbs initiator RUCI2 (PCy3)2(CHPh) and triphenylphosphine (PPhs) as modulator. To come up with disks with sufficient mechanical strength, poly (amide) membranes were soaked with the polymerization mixture (Scheme 33). This way, membrane-supported monolithic disks up to 2 mm in thickness were realized. These disks were successfully used for the preconcentration of iodine and selected organic solutes from dilute aqueous samples by SPE. Quantitative measurement of the extracted solutes was achieved by diffuse-reflectance spectroscopy (DRS) directly on the surface of the disk. 

In the final step of the process, the primary alkyl iodide is then treated with triphenylphosphine (PPhs), wliich functions as a nucleophile, giving another Sn2 reaction, to afford a phosphonium salt. 

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