Category Ranking
98%
Total Visits
921
Avg Visit Duration
2 minutes
Citations
20
Article Abstract
The reactivity of diethyl azodicarboxylate (DEAD)/diisopropyl azodicarboxylate (DIAD) with P(III) compounds bearing oxygen or nitrogen substituents is explored. Compounds with structures quite different from that of Morrison-Brunn-Huisgen intermediate R'(3)P(+)N(CO(2)R)N(-)(CO(2)R) (1), observed in the Mitsunobu reaction, have been established by using X-ray crystallography and NMR spectroscopy. Thus reactions with X(6-t-Bu-4-Me-C(6)H(2)O)(2)P-NH-t-Bu [X = S (8), CH(2) (9)] or XP(mu-N-t-Bu)(2)P-NH-t-Bu [X = Cl (14) or NH-t-Bu (15)] and DEAD/DIAD lead to phosphinimine-carbamate-type of products X[6-t-Bu-4-Me-C(6)H(2)O](2)P[N-t-Bu][N(CO(2)R)NH(CO(2)R)] [X = S, R = Et (16); X = CH(2), R = Et (17); X = CH(2), R = i-Pr (18)] or XP(mu-N-t-Bu)(2)P(N-t-Bu)[N-(CO(2)-i-Pr)-N(H)(CO(2)-i-Pr) [X = Cl (19), NH-t-Bu (20)]. Treatment of 19 with 2,2,2-trifluoroethanol afforded the product [(CF(3)CH(2)O)P(mu-N-t-Bu)(2)P(+)(NH-t-Bu)[N(CO(2)-i-Pr)(HNCO(2)-i-Pr)]][Cl(-)] (21) whose structure is close to one of the intermediates proposed in the Mitsunobu reaction. The isocyanate CH(2)(6-t-Bu-4-Me-C(6)H(2)O)(2)P-NCO (10) underwent 1,3-(P,C) cycloaddition with DEAD/DIAD to lead to CH(2)(6-t-Bu-4-Me-C(6)H(2)O)(2)P[N(CO(2)R)N(CO(2)R)-C(O)-N] [R = Et (22), i-Pr (23)]. Reaction of 22-23 with 1,1'-bi-2-naphthol or catechol leads to novel tetracoordinate CH(2)(6-t-Bu-4-Me-C(6)H(2)O)(2)P(2,2'-OC(10)H(6)-C(10)H(6)-OH)[NC(O)-(CO(2)R)NH(CO(2)R)] [R = Et (24), i-Pr (25)] or pentacoordinate CH(2)(6-t-Bu-4-Me-C(6)H(2)O)(2)P(1,2-O(2)C(6)H(4))[NHC(O)-N(CO(2)R)NH(CO(2)R)] [R = Et (26), i-Pr (27)] compounds in which the original NCO residue is retained; this mode of reactivity is quite different from that observed for the MBH betaine 1. In 27, the nitrogen, rather than the oxygen, occupies an apical position of the trigonal bipyramidal phosphorus violating the commonly assumed preference rules for apicophilicity. It is shown that the previously reported azide derivative 3, obtained from the reaction of 11 with DIAD, undergoes a Curtius-type rearrangement to lead to the fused cyclodiphosphazane [(CH(2)(6-t-Bu-4-Me-C(6)H(2)O)(2))P(OC(O-i-Pr)NN(CO(2)-i-Pr)N)](2) (28); this compound is in equilibrium with its monomeric form in solution at >300 K. Finally, reaction of S(6-t-Bu-4-Me-C(6)H(2)O)(2)P(OPh) (13) with DIAD gave the hexacoordinate compound S[6-t-Bu-4-Me-C(6)H(2)O](2)P(OPh)[N(CO(2)-i-Pr)NC(O-i-Pr)O] (30) with an intramolecular S-->P bond. X-ray crystallographic evidence for compounds 16, 19, 21, 22, 25, 27, 28, and 30 has been provided.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jo035634d | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Enhanced Reactivity of N-heterocyclic Halophosphines and Phosphenium Cations: The Activation of Carbon─Heteroatom and Boron─Heteroatom Bonds.
Chemistry
August 2025
Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, Pardubice, 53209, Czech Republic.
N-heterocyclic phosphines (NHPs), and especially their ionic derivatives, phosphenium cations, have gained significant attention not only as isoelectronic species to N-heterocyclic carbenes (NHCs) but mainly, as highly Lewis acidic, active organocatalysts. A novel type of saturated NHPs has been introduced, with the nitrogen atoms substituted by phosphoramidothioates-{[κ-O,O-(OCHC(Me)CHO)P(= S)]-μ-[NCHCHN]}PX, where X = F, Cl, Br, I, H, Ph, and their derivatives. Thanks to an increased positive charge at the P(III) atom, these compounds are prone to activate C─O, B─H, B─C, or B─F bonds and open cyclic ethers through the formation of intermediate species-phosphenium cations.
View Article and Find Full Text PDFaNHC-Stabilized Low-Valent Phosphorus Compound: Exploring Dual Catalytic Activity via Nucleophilicity and P(I)/P(III) Redox Reactivity.
J Am Chem Soc
July 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur, Kolkata 741246, India.
In this work, we present the synthesis and detailed characterization of a low-valent phosphorus compound, mesoionic N-heterocyclic phosphinidene (mNHP, ), stabilized by an abnormal N-heterocyclic carbene (aNHC). Natural resonance theory analysis and the formation of a bis-borane adduct (confirmed by a single-crystal X-ray diffraction study) revealed that the phosphorus center in mNHP has access to two lone pairs of electrons, as expected for a P(I) species. Beyond its structural characterization, we also investigated both the nucleophilic and redox reactivity of mNHP.
View Article and Find Full Text PDFScalable Multistep One-Pot Synthesis of Natural and Modified Nucleoside Triphosphates.
J Org Chem
May 2025
Department of Pharmaceutical Sciences, University of California, Irvine, California 92697-3958, United States.
Polymerases are among the most powerful tools in the molecular biology toolbox; however, access to large quantities of chemically modified nucleoside triphosphates for diverse applications remains hindered by the need for purification by high-performance liquid chromatography (HPLC). Here, we describe a scalable approach to modified nucleoside triphosphates that proceeds through a P(III)-P(V) mixed anhydride intermediate obtained from the coupling of a P(III) nucleoside phosphoramidite and a P(V) pyrene pyrophosphate reagent. The synthetic strategy allows the coupling, oxidation, and deprotection steps to proceed as stepwise transformations in a single one-pot reaction.
View Article and Find Full Text PDFAdvancing metallomimetic catalysis through structural constraints of cationic P species.
Chem Commun (Camb)
April 2025
School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
In recent years, the concept of structural constraints on the main-group (MG) centers has emerged as a powerful strategy to enhance their reactivity. Among these, structurally constrained (SC) phosphorus centers have garnered significant attention due to their ability to cycle between two stable oxidation states, P(III) and P(V), making them highly promising for small molecule activation and catalysis. Structural constraints grant phosphorus centers transition metal (TM)-like reactivity, enabling the activation of small molecules by these SC P(III) centers, a reactivity previously inaccessible with conventional phosphines or other phosphorus derivatives.
View Article and Find Full Text PDFReactions of chalcogens and borane with phosphazane macrocycles assembled from diethanolamine and PN building blocks.
Dalton Trans
March 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Mohali 140306, Punjab, India.
Phosphazanes of the type [ClP(μ-NR)] are excellent building blocks for the formation of a range of macrocycles. The condensation reaction of the bifunctional linkers, -substituted diethanolamine with cyclodiphosphazane, [ClP(μ-NBu)] leads to the formation of dimeric macrocycles, [{P(μ-NBu)}{O(CH)N(R)(CH)O}]; (R = Me (1), Ph (2)). Furthermore, the P centres of 1 and 2 were oxidized with chalcogens (O, S, and Se) to afford the corresponding P macrocycles - [{(O)P(μ-NBu)}{O(CH)N(R)(CH)O}] (R = Me (3), Ph (4)); [{(S)P(μ-NBu)}{O(CH)N(R)(CH)O}] (R = Me (5), Ph (6)) and [{(Se)P(μ-NBu)}{O(CH)N(R)(CH)O}] (R = Me (7), Ph (8)).
View Article and Find Full Text PDF