Beyond Triphenylphosphine: Advances on the Utilization of Triphenylphosphine Oxide.

Triphenylphosphine oxide is a well-known industrial waste byproduct, and thousands of tons of it are generated every year. Due to its chemical stability and limited applications, settlement of this waste issue has drawn extensive attention from chemists. The reduction of triphenylphosphine oxide to triphenylphosphine is heretofore the most employed solution, and is well reviewed. In view of our recent studies on the selective and efficient conversion of Ph3P(O) to other valuable organophosphorus chemicals by using sodium, the present perspective mainly highlights the advances on the utilization of Ph3P(O) to prepare a diverse range of functional organophosphorus compounds, except Ph3P, via selective P-C, C-H, and P-O bond cleavages.

Reductive Coupling of P(O)-H Compounds and Aldehydes for the General Synthesis of Phosphines and Phosphine Oxides.

A novel strategy for the selective construction of a C(sp3)-P(III) or -P(V) bond from >P(O)-H compounds and aldehydes is disclosed. By using the H3PO3/I2 system, various secondary phosphine oxides could react with both aromatic and aliphatic aldehydes to afford valuable phosphines (isolated as sulfides) and phosphine oxides in good yields. This method features a wide substrate scope and simple reaction conditions and avoids the use of toxic halides and metals.

Ligand-Free Iron-Catalyzed Construction of C-P Bonds via Phosphorylation of Alcohols: Synthesis of Phosphine Oxides and Phosphine Compounds.

An efficient method for the construction of C-P(V) and C-P(III) bonds via the iron-catalyzed phosphorylation of alcohols under ligand-free conditions is disclosed. This strategy represents a straightforward process to prepare a series of phosphine oxides and phosphine compounds in good to excellent yields from the readily available alcohols and P-H compounds. A plausible mechanism is also proposed. We anticipate that this mode of transforming simple alcohols would apply in chemical synthesis widely.

Chiral α-Aminophosphonates as Ligands in Copper-Catalyzed Asymmetric Oxidative Coupling of 2-Naphthols.

Chiral α-aminophosphonates with adjacent carbon and phosphonate stereogenic centers have been employed as ligands in the copper-catalyzed oxidative coupling of 2-naphthols, resulting in the production of chiral BINOLs in favorable yields and moderate to good enantiomeric excess. This represents the first application of chiral P-based ligands to enable such a transformation. The synthesis of these chiral α-aminophosphonate ligands offers a significant advantage over approaches that typically necessitate elaborate synthetic processes for chiral ligand production.

Water-Promoted Mild and General Michaelis-Arbuzov Reaction of Triaryl Phosphites and Aryl Iodides by Palladium Catalysis.

A Pd-catalyzed relatively general Michaelis-Arbuzov reaction of triaryl phosphites and aryl iodides for preparing useful aryl phosphonates was developed. Interestingly, water can greatly facilitate the reaction through a water-participating phosphonium intermediate rearrangement process, which also makes the reaction conditions rather mild. In comparison with the known methods, this reaction is milder and more general, as it exhibits excellent functional group tolerance, can be applied to various triaryl phosphites and aryl iodides, and can be extended to aryl phosphonites and phosphinites. A gram-scale reaction with a low catalyst loading also revealed its practicality and potential in large-scale preparation.

Palladium-Catalyzed Decarbonylative Michaelis-Arbuzov Reaction of Carboxylic Acids and Triaryl Phosphites.

A Pd-catalyzed decarbonylative Michaelis-Arbuzov reaction of carboxylic acids and triaryl phosphites for preparing aryl phosphonates under anhydride-free conditions has been reported. In this context, triaryl phosphites serve as both reagents for activating the carboxylic acids and substrates for the reaction. There have been no reports to date of efficient and direct methods for the in situ activation of carboxylic acids using triaryl phosphites. In comparison to known methods, this reaction avoids the use of organohalides and has an excellent functional group tolerance for the synthesis of various aryl phosphonates from triaryl phosphites and carboxylic acids. This reaction is scalable and applicable to the synthesis of aryl phosphonates featuring bioactive fragments.