Photoinduced transition-metal and external photosensitizer free cross-coupling of aryl triflates with trialkyl phosphites

Photoinduced phosphonation of aryl triflates with trialkyl phosphites via a tandem single-electron-transfer, C–O bond cleavage and Arbuzov rearrangement process in the absence of transition-metal and external photosensitizer is reported herein....

Catalytic phosphonylation of C=X electrophiles

A method for the catalytic phosphonylation of C = X electrophiles has been developed. Pyridinium perchlorate is an effective catalyst for the phosphonylation reaction of trialkyl phosphites with various electrophiles C = X (X = O, S, N). The reaction leads to the formation of corresponding α-substituted phosphonates in high yields. The reaction leading to the formation of bisphosphonates represents the highest interest. It was found that the nucleo philic attack of triethyl phosphite on the electron-deficient carbon of the C = X group leads to the formation of beta ine, which reacts with pyridinium perchlorate to form alkoxyphosphonium perchlorate and pyridine. Quasiphosphonium salt is unstable and decomposes to form phosphonate, alkene, and perchloric acid, which reacts with pyridine to regenerate pyridinium perchlorate. The intermediate formed from the pyridinium halide decomposes to form alkyl halide. The general strategy of the proposed method for introducing phosphonate groups into a polyprenyl mole cule consisted in the sequential treatment of hydroxyl-containing a compound with the Swern reagent with the con version of the C—OH group into a carbonyl one. Subsequent phosphonylation of the carbonyl-containing interme diate with the reagent (EtO)3P/[PyH] + ClO 4– leads to the formation of hydroxyalkylbisphosphonate. The synthe sized prenyl bisphosphonates have a pronounced biological activity. These include, for example, enolpyruvylshikimate-3- phosphate synthase (EPSP), farnesyl protein transferase (FPTase), as well as HIV protease, which are of interest as potential biologically active substances.

Regioselective O/C phosphorylation of α-chloroketones: a general method for the synthesis of enol phosphates and β-ketophosphonates via Perkow/Arbuzov reaction

A highly regioselective O/C phosphorylation of α-chloroketones with trialkyl phosphites was developed in the preparation of enol phosphates and β-ketophosphonates.

Iodine catalyzed one-pot four component synthesis of coumarinyl phosphoramidates via sequential addition of reactants

An unprecedented synthetic route for the preparation of a library of novel coumarinyl phosphoramidate derivatives via iodine catalysed one-pot four component reactions of ethyl 4-bromo-3-oxo-alkanoate, sodium azide, trialkyl phosphites, and phenols in ethanol is reported.

New Bioactive Esters and Phosphonates Semisynthesized From (±)-Vasicinone: An Alkaloid Isolated From Peganum harmala

A series of N-tosyl α-amino acids 2a-e, prepared using a tosyl chloride protecting group, was condensed with (±)-vasicinone 1, isolated from the seeds of the plant Peganum harmala, to generate the corresponding esters 3a-e and 3b′-e′. (±)-Vasicinone 1 was also reacted with chloroacetic acid chloride to afford a new chlorinated ester 4 which was refluxed with trialkyl phosphites to give 2 new phosphonates 5a,b. All synthesized compounds were characterized with the help of spectroscopic means, including NMR (1H, 13C, and 31P) and ES-HRMS, and then screened for their in vitro anti-acetylcholinesterase (AChE), anti-5-lipoxygenase (5-LOX), and cytotoxic activities (MCF-7, OVCAR-3, and HCT-116 cell lines). Most synthesized derivatives exhibited a cytotoxic activity against 3 cell lines used. The phosphonate derivative 5b was found to be the most active one (IC50 = 63.7 ± 1.4 µM) against AChE enzyme. Only 2 diastereoisomers 3e and 3e′ exhibited activity against 5-LOX enzyme with IC50 values of 63.1 ± 4.2 and 79.2 ± 8.3 µM, respectively.