Zarytova V F, Knorre D G
Nucleic Acids Res. 1984 Feb 24;12(4):2091-110. doi: 10.1093/nar/12.4.2091.
Phosphotriester condensation (RO)(R'O)PO-2 (PDE) + R"OH (RO)(R'O)(R"O)PO (PTE) in the presence of arylsulfonyl chloride (ArSO2Cl) as well as arylsulfonyl azolides proceeds in two steps as revealed by 31P NMR spectroscopy. Pyrophosphotetraester (PPTE) accumulates in over 80% yield in the first step and converts to PTE in the second one. Nucleophilic catalysts of pyridine type (Nu1) are necessary in the first step. The second step is catalyzed by Nu1 as well as by catalysts of the tetrazole type (Nu2H). Base catalysis operates in the latter case. With Nu1 catalysts (pyridine, 4-N,N-dimethylaminopyridine, N-methylimidazole) the general scheme may be presented as follows: ArSO2Cl + Nu1 in equilibrium ArSO2Nu+1 + Cl-; ArSO2Nu+1 + PDE----(RO)(R'O)P(O)OSO2Ar (I); I + Nu+1----(RO)(R'O)P(O)Nu+1 (II); II + PDE in equilibrium [(RO)(R'O)PO]20; II + R"OH----(RO)(R'O)(R"O)PO. Catalysts of Nu2H type don't accelerate PPTE formation. In the second step they participate most probably in the process PPTE + Nu2H in equilibrium (RO)(R'O)P(O)Nu2 (III) + PDE; III + R"OH----(RO)(R'O)(R"O)PO + H+. The latter step is subjected to strong base catalysis.
在芳基磺酰氯（ArSO₂Cl）以及芳基磺酰叠氮化物存在的情况下，磷酸三酯缩合反应（RO）（R'O）PO⁻²（PDE）+ R''OH→（RO）（R'O）（R''O）PO（PTE）分两步进行，³¹P NMR光谱显示了这一点。焦磷酸四酯（PPTE）在第一步中以超过80%的产率积累，并在第二步中转化为PTE。第一步需要吡啶型亲核催化剂（Nu1）。第二步由Nu1以及四唑型催化剂（Nu2H）催化。在后一种情况下存在碱催化。对于Nu1催化剂（吡啶、4-N，N-二甲基氨基吡啶、N-甲基咪唑），一般反应历程如下：ArSO₂Cl + Nu1⇌ArSO₂Nu⁺¹ + Cl⁻；ArSO₂Nu⁺¹ + PDE→（RO）（R'O）P（O）OSO₂Ar（I）；I + Nu⁺¹→（RO）（R'O）P（O）Nu⁺¹（II）；II + PDE⇌[（RO）（R'O）PO]₂O；II + R''OH→（RO）（R'O）（R''O）PO。Nu2H型催化剂不会加速PPTE的形成。在第二步中，它们很可能参与了PPTE + Nu2H⇌（RO）（R'O）P（O）Nu2（III）+ PDE的过程；III + R''OH→（RO）（R'O）（R''O）PO + H⁺。后一步受到强碱催化。
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