Stereochemistry of internucleotide bond formation by the H-phosphonate method. Part 3: Investigations on a mechanism of asymmetric induction

The stereochemistry of H-phosphonate diester bond formation (including internucleotide ones) with ribonucleoside H-phosphonates as substrates has been investigated using 31P NMR spectroscopy. It was found that the reactions investigated owe their stereoselectivity to a dynamic kinetic asymmetric transformation. The absolute configurations of the compounds involved in the reaction pathways were tentatively assigned on the basis of their 31P NMR chemical shifts and their correctness was verified for the H-phosphonic–pivalic mixed anhydrides and H-phosphonate aryl esters.

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