Enhancing Prebiotic Phosphorylation and Modulating the Regioselectivity of Nucleosides with Diamidophosphate†

Where Does the Proton Go? Structure and Dynamics of Hydrogen-Bond Switching in Aminophosphine Chalcogenides

Aminophosphates are the focus of research on prebiotic phosphorylation chemistry. Their bifunctional nature also makes them a powerful class of organocatalysts. However, the structural chemistry and dynamics of proton-binding in phosphorylation and organocatalytic mechanisms are still not fully understood. Aminophosphine chalcogenides, preserving the central H2N-P+-Ch- structural motif, represent well-suited molecular models that mimic proton-binding, hydrogen-bond switching and supramolecular self-assembling behavior of catalytically and prebiotically relevant molecules. Through spectroscopic (IR, 1H DOSY, 15N NMR), molecular dynamics, and computational investigations, the dynamic proton switching capability of aminophosphate analogs was demonstrated. It was shown under which conditions the amino (NH2) or chalcogen (Ch) functions in H2N-P+-Ch- structural units are protonated. In fact, all conceivable modes of hydrogen-bonding were identified, revealing substantial differences between the oxygen derivative and the heavier congeners. Using coordinating anions, supramolecular zigzag- and cube-shaped arrangements were found in the solid-state and in solution. After break-up of the cube structure, the sulfides and selenides no longer form stable interactions with HCl molecules. In the absence of coordinating anions, however, protonation of the chalcogen function is preferred. In contrast to the oxygen derivative, the heavier protonated congeners show dynamic intramolecular proton-hopping between the chalcogen and the amino function.

Direct conversion of various phosphate sources to a versatile P-X reagent [TBA][PO2X2] via redox-neutral halogenation

Inorganic phosphates hold significant potential as ideal natural building blocks, forming a fundamental basis for organic and biochemical synthesis. However, their limited solubility, inherent chemical stability, and low reactivity pose substantial challenges to converting phosphates into organophosphates under mild conditions. This study introduces an efficient method for the direct conversion of phosphates into P(V)-X reagents, [TBA][PO2X2] (X = Cl, F), via a redox-neutral halogenation process. This method utilizes cyanuric chloride (or cyanuric fluoride) as the halogenation reagent, in combination with 1-formylpyrrolidine and tetrabutylammonium chloride (TBAC), under ambient conditions. The approach enables effective halogenation conversion for various P(V) sources, including orthophosphates, pyrophosphoric acid, Na3P3O9 and P2O5. Furthermore, we demonstrate the synthetic utility of the P(V)-Cl reagent in the phosphorylation of diverse O-, S-, N- and C-nucleophiles. Key advantages of this conversion process include the use of inexpensive and readily available chemicals, the avoidance of high-energy redox reactions, and the generation of a reactive yet stable P(V)-X reagent.

A Prebiotic Precursor to Life's Phosphate Transfer System with an ATP Analog and Histidyl Peptide Organocatalysts

Biochemistry is dependent upon enzyme catalysts accelerating key reactions. At the origin of life, prebiotic chemistry must have incorporated catalytic reactions. While this would have yielded much needed amplification of certain reaction products, it would come at the possible cost of rapidly depleting the high energy molecules that acted as chemical fuels. Biochemistry solves this problem by combining kinetically stable and thermodynamically activated molecules (e.g., ATP) with enzyme catalysts. Here, we demonstrate a prebiotic phosphate transfer system involving an ATP analog (imidazole phosphate) and histidyl peptides, which function as organocatalytic enzyme analogs. We demonstrate that histidyl peptides catalyze phosphorylations via a phosphorylated histidyl intermediate. We integrate these histidyl-catalyzed phosphorylations into a complete prebiotic scenario whereby inorganic phosphate is incorporated into organic compounds though physicochemical wet-dry cycles. Our work demonstrates a plausible system for the catalyzed production of phosphorylated compounds on the early Earth and how organocatalytic peptides, as enzyme precursors, could have played an important role in this.