Functionalization of Intact Trimetaphosphate: A Triphosphorylating Reagent for C, N, and O Nucleophiles
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manuscript_pdfa.pdf
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main article
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1.08 MB
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Author(s)
Shepard, Scott M.
Cummins, Christopher C
Date Issued
January 2019
Journal
Journal of the American Chemical Society
Publisher
American Chemical Society (ACS)
Citation
Shepard, Scott M. and Christopher C. Cummins. "Functionalization of Intact Trimetaphosphate: A Triphosphorylating Reagent for C, N, and O Nucleophiles." Journal of the American Chemical Society 141, 5 (January 2019): 1852-1856 © 2019 American Chemical Society
Version
Author's final manuscript
Abstract
Trimetaphosphate (TriMP, [P₃O9]³⁻) reacts with PyAOP ([(H₈C₄N)₃PON₄C₅H₃][PF₆]) to yield an activated TriMP, [P₃O₉P(NC₄H₈)₃]⁻ (1), incorporating a phosphonium moiety. Anion 1 is isolated as its bis(triphenylphosphine)iminium (PPN) salt in 70% yield and phosphorylates nucleophiles with elimination of phosphoramide OP(NC₄H₈)₃. Treatment of 1 with amines HNR¹R² generates [P₃O₈NR¹R²]²⁻(2a: R¹ = R² = Et; 2b: R¹ = H, R² = tBu) in greater than 70% yield as mixed PPN and alkyl ammonium salts. Treatment of 1 with primary alcohols in the presence of a tertiary amine base results in salts of intact TriMP alkyl esters [P₃O₉R]²⁻(3a: R = Me; 3b: R = Et) in greater than 60% isolated yield. Reaction of 1 with [PPN][H₂PO4] provides orthophosphoryl TriMP (4, [P₄O1₂H₂]²⁻) in 40% yield as the PPN salt. Treatment of 1 with Wittig reagent H₂CPPh₃ (4 equiv) provides phosphorus ylide [P₃O₈CHPPh₃]²⁻ (5) in 61% yield as a mixed salt. Ylide 5 reacts with water to provide [P₃O₈Me]²⁻(6) and with aldehydes to give olefins [P₃O₈CHCHR]²⁻ (7a: R = H; 7b: R = 4-C₆H₄Br), products in which one TriMP oxygen is replaced by a phosphonate P–C linkage. Treatment of intact TriMP derivatives 2a, 2b, 3a, and 7a with aqueous tetrabutylammonium hydroxide results in ring opening to linear triphosphate derivatives. X-ray crystal structures are provided for salts of 1, 2a, 3a, and 4.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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DOI of Published Version
https://doi.org/10.1021/jacs.8b12204
