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Chemicals >> Reducing Agents


See also: tributylphosphine, trimethylphosphine, triethylphosphine

Name Reactions

Mitsunobu Reaction


Staudinger Reaction

Recent Literature

A palladium-catalyzed reductive carbonylation enables a facile and practical synthesis of aromatic aldehydes from aryl iodides and HCOOH. HCOOH serves not only as convenient and environmental-friendly C1 source but also as the reviving agent in the reductive elimination process of a Pd-catalyst.
G. Sun, X. Lv, M. Lei, L. Hu, Org. Lett., 2017, 19, 4235-4238.

An efficient catalytic Staudinger reduction at room temperature provides structurally diverse amines from azides in excellent yields in the presence of catalytic amounts of triphenylphosphine and diphenyldisiloxane as terminal reducing agent. The reaction exhibits high chemoselectivity and tolerates nitriles, alkenes, alkynes, esters, and ketones.
D. C. Lenstra, J. J. Wolf, J. Mecinović, J. Org. Chem., 2019, 84, 6536-6545.

A mild transition-metal- and photosensitizer-free photoredox system based on the combination of NaI and PPh3 enables a highly selective reduction of nitroarenes. This protocol tolerates a broad range of reducible functional groups such as halogen (even I), aldehyde, ketone, carboxyl, and cyano.
Z. Qu, X. Chen, S. Zhong, G.-J. Deng, H. Huang, Org. Lett., 2021, 23, 5349-5353.

A low-valent tungsten complex catalyzes a visible light mediated amination of boronic acids with nitroaromatics at ambient temperature. With readily available W(CO)6 as a precatalyst under external-photosensitizer-free conditions, nitroaromatics smoothly undergo C-N coupling reactions with boronic acids, delivering structurally diverse secondary amines in good yields.
H. Song, Y. Shen, H. Zhou, D. Ding, F. Yang, Y. Wang, C. Xu, X. Cai, J. Org. Chem., 2022, 87, 5303-5314.

A new, mild protocol for deoxygenation of various phosphine oxides with retention of configuration is described. Mechanistic studies regarding the oxygen transfer between the starting phosphine oxide and triphenylphosphine are also presented.
H.-C. Wu, J.-Q. Yu, J. B. Spencer, Org. Lett., 2004, 6, 4675-4678.

A rhodium-catalyzed methylenation-hydrogenation cascade process allows the homologation of carbonyl compounds to alkanes in high yields.
H. Lebel, C. Ladjel, J. Org. Chem., 2005, 70, 10159-10161.

A reduction of sulfonyl chlorides in the presence of triphenylphosphine in toluene enables an efficient and convenient method for the synthesis of arylthiols.
E. V. Bellale, M. K. Chaudhari, K. G. Akamanchi, Synthesis, 2009, 3211-3213.

In a mild reduction of sulfoxides, sulfides are obtained in excellent yields when aliphatic and aromatic sulfoxides were treated with SOCl2 as a catalyst and Ph3P in THF at room temperature.
Y. Jang, K. T. Kim, H. B. Jeon, J. Org. Chem., 2013, 78, 6328-6331.

A CuI-catalyzed coupling reaction of aryl iodides and sulfur powder takes place in the presence of K2CO3 at 90°C in DMF as solvent. The coupling mixture is directly treated with NaBH4 or triphenylphosphine to afford aryl thiols in good to excellent yields. A wide range of substituted aryl thiols that bear methoxy, hydroxyl, carboxylate, amido, keto, bromo, and fluoro groups can be synthesized.
Y. Jiang, Y. Qin, S. Xie, X. Zhang, J. Dong, D. Ma, Org. Lett., 2009, 11, 5250-5253.

A stereoinvertive deoxygenation of trans-3-arylglycidates provides thermodynamically less stable (Z)-cinnamate esters by using nickel triflate and triphenylphosphine. The reaction offers broad functional group tolerance and affords the corresponding (Z)-cinnamate esters in high yields and with moderate to high E/Z ratios.
S. Akkarasamiyo, S. Chitsomkhuan, S. Buakaew, J. S. M. Samec, P. Chuawong, P. Kuntiyong, Synlett, 2022, 33, 1353-1356.

In the presence of Ph3P and a catalytic amount of Fe(TCP)Cl, ketenes react with EDA to give allenes in high yields under neutral conditions. By employing a chiral phosphine, allenes could be synthesized with high enantioselectivity in good yields.
C.-Y. Li, X.-B. Wang, X.-L. Sun, Y. Tang, J.-C. Zheng, Z.-H. Xu, Y.-G. Zhou, L.-X. Dai, J. Am. Chem. Soc., 2007, 129, 1494-1495.

Various carboxylic acids were converted into acyl azides in excellent yields in the presence of trichloroacetonitrile, triphenylphosphine and sodium azide at room temperature. The reaction allows the preparation of dipeptides without deprotection or rearrangement during the reaction.
J.-G. Kim, D. O. Jang, Synlett, 2008, 2072-2074.

Treatment of alcohols with a mixture of triphenylphosphine, carbon tetrachloride, oxime, and DBU in the presence of catalytic amounts of tetrabutylammonium iodide in refluxing acetonitrile regioselectively furnishes the corresponding O-alkyl ethers in good yields.
M. N. S. Rad, A. A. Khalafi-Nezhad, F. Karimitabar, S. Behrouz, Synthesis, 2010, 1724-1730.

Alkyl nitrites were prepared in good to excellent yields by treatment of alcohols and thiols with triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone/Bu4NNO2 in acetonitrile. This method allows a selective conversion of primary alcohols in the presence of secondary and tertiary alcohols and thiols.
B. Akhlaghinia, A. R. Pourali, Synthesis, 2004, 1747-1749.

A Ph3P/I--promoted dihalogenation of epoxides provides 1,2-dihalides in the presence of XCH2CH2X (X = Cl or Br) as the solvent and halogen source. All reagents are widely available and easy to handle. The protocol offers mild conditions and operational simplicity.
J. Long, J. Chen, R. Li, Z. Liu, X. Xiao, J.-H. Ling, X. Zheng, J.-C. Xiao, Synlett, 2019, 30, 181-184.

A highly regioselective chlorothiolation of alkenes with sulfonyl chlorides is compatible with a variety of functional groups and can be scaled up to the gram scale. The employment of readily available reactants and mild reaction conditions makes this process very practical.
J. Wei, S. Liang, L. Jiang, Y. Mumtaz, Y.-b. Yi, J. Org. Chem., 2020, 85, 977-984.

In the presence of trifluoromethanesulfonyl chloride, triphenylphosphine, and sodium iodide, a broad range of thiocarbamyl fluorides and isothiocyanates can be synthesized from secondary and primary amines in good yields, respectively. The reactions offer good functional group compatibility.
J. Wei, S. Liang, L. Jiang, W. Yi, J. Org. Chem., 2020, 85, 12374-12381.

In the presence of trifluoromethanesulfonyl chloride, triphenylphosphine, and sodium iodide, a broad range of thiocarbamyl fluorides and isothiocyanates can be synthesized from secondary and primary amines in good yields, respectively. The reactions offer good functional group compatibility.
J. Wei, S. Liang, L. Jiang, W. Yi, J. Org. Chem., 2020, 85, 12374-12381.

An efficient, practical photocatalytic deoxygenation/defluorination protocol provides γ,γ-difluoroallylic ketones from commercially available aromatic carboxylic acids and α-trifluoromethyl alkenes in the presence of triphenylphosphine. The protocol offers good functional group tolerance and a broad substrate scope.
Y.-Q. Guo, R. Wang, H. Song, Y. Liu, Q. Wang, Org. Lett., 2020, 22, 709-713.

A photocatalyzed intramolecular cyclization of biarylcarboxylic acids with triphenylphosphine as an inexpensive and effective deoxygenative reagent provides fluorenones via formation of acyl radicals, which quickly undergo intramolecular radical cyclization. Reactions in the presence of air and continuous flow photoredox technology demonstrate the generality and practicality of this process.
Y. Li, W. Xu, C. Zhu, J. Xie, Synlett, 2021, 32, 387-390.

A reaction sequence involving a Wittig reaction, a Staudinger reaction, an aza-Wittig reaction, a 6π-3-azatriene electrocyclization, and a 1,3-H shift enables a quick one-pot synthesis of polysubstituted pyridines in very good yields from aldehydes, phosphorus ylides, and propargyl azide.
H. Wei, Y. Li, K. Xiao, B. Cheng, H. Wang, L. Hu, H. Zhai, Org. Lett., 2015, 17, 5974-5977.

A reductive cyclization of o-nitrobenzylidene amines under microwave conditions in the presence of MoO2Cl2(dmf)2 as catalyst and Ph3P as reducing agent delivers 2-aryl-2H-indazoles in good yields.
A. H. Moustafa, C. C. Malakar, N. Aljaar, E. Merisor, J. Conrad, U. Beifuss, Synlett, 2013, 24, 1573-1577.

A one-step reaction to assemble pyrroles from α,β-unsaturated imines and acid chlorides is mediated by triphenylphosphine, which eliminates phosphine oxide to allow cyclization. This reaction has been employed to access broad range of pyrroles via modulation of the two building blocks and applied as well to the synthesis of lukianol A.
Y. Lu, B. A. Arndtsen, Org. Lett., 2009, 11, 1369-1372.

A new and efficient three-component reaction between dialkyl acetylenedicarboxylates, aromatic amines, triphenylphosphine, and arylglyoxals afforded polysubstituted pyrrole derivatives in high yields. The reactions were performed in dichloromethane at room temperature and under neutral conditions.
M. Anary-Abbasinejad, K. Charkhati, H. Anaraki-Ardakani, Synlett, 2009, 1115-1117.

A reaction between dialkyl acetylenedicarboxylates and β-aminoketones promoted by triphenyl­phosphine allows an efficient one-pot synthesis of polysubstituted 2,5-dihydropyrrole derivatives. The prepared 2,5-dihydropyrroles can be easily oxidized to the corresponding pyrrole derivatives with chromium trioxide.
M. Anary-Abbasinejad, E. Poorhassan, A. Hassanabadi, Synlett, 2009, 1929-1932.

A novel, efficient, and general domino reaction of 2-acylaziridines with the Huisgen zwitterions furnishes 2-pyrazolines. A possible mechanism for the domino sequence is proposed.
S.-L. Cui, J. Wang, Y.-G. Wang, Org. Lett., 2008, 10, 13-16.

In one-pot Wittig olefination reactions of aldehydes, an excess of rasta resin-PPh3, a heterogeneous polystyrene-based phosphine, was used for the in situ generation of the phosphorane reactant and enabled the isolation of a high yield of very pure alkene product after only filtration and solvent removal. The excellent results obtained in this study are attributed to the flexible nature of the rasta resin structure.
P. S.-W. Leung, Y. Teng, P. H. Toy, Synlett, 2010, 1997-2001.

A polymer-bound, triphenylphosphine-supported reagent allows a one-pot, two-step synthesis of secondary amines from the corresponding azide and a reactive alkyl halide.
S. Ayesa, B. Samuelsson, B. Classon, Synlett, 2008, 89-93.

Triphenylphosphine mediates a metal-free, intermolecular, reductive amination between nitroarenes and boronic acids at ambient temperature under visible-light irradiation without any photocatalyst. A wide range of nitroarenes underwent C-N coupling with aryl-/alkylboronic acids providing high yields.
K. Manna, T. Ganguly, S. Baitalik, R. Jana, Org. Lett., 2021, 23, 8634-8639.

A mechanochemical synthesis of 2,5-disubstituted 1,3,4-oxadiazoles is an environmentally benign alternative to conventional solvent-based methods. In the presence of triphenylphosphine and trichloroisocyanuric acid, N-acylbenzotriazoles condense with acylhydrazides to provide oxadiazoles derivatives in very good yields within minutes. A range of reactive functionalities was well tolerated.
D. Yamano, N. Wiriya, W. Phakhodee, S. Wet-osot, M. Pattarawarapan, Synlett, 2022, 33, 1458-1462.

The combination of Ph3P and I2 promotes a synthesis of benzimidazolones from readily accessible hydroxamic acids. Upon Lossen-type rearrangement of the O-activated hydroxamic acids, the in situ generated isocyanates undergo an intramolecular attack by ortho N-nucleophiles producing the cyclized products in good yields under mild conditions.
N. Wiriya, D. Yamano, S. Hongsibsong, M. Pattarawarapan, W. Phakhodee, Synlett, 2022, 33, 1468-1472.

An efficient intermolecular amidation of quinoline N-oxides with sulfonamides in the presence of PhI(OAc)2 and PPh3 provides N-(quinolin-2-yl)sulfonamides in very good yields.
X. Yu, S. Yang, Y. Zhang, M. Guo, Y. Yamaoto, M. Bao, Org. Lett., 2017, 19, 6088-6091.

3-Hydroxyquinoline-4(1H)-ones (3HQs) are privileged structural motifs. Phosphine mediates a redox transformation of easily accessible 1-(2-nitroaryl)prop-2-ynones to 3HQs under neutral conditions. The synthetic utility of this formal intramolecular oxyamination of α,β-ynones is demonstrated in the total synthesis of japonine, its analogs, and rare quinoline derivatives.
L. Dutta, S. S. V. Ramasastry, Org. Lett., 2022, 24, 7665-7670.