Oligomeric building block approach to the synthesis of diastereomerically pure pentathymidine 3',5'-methanephosphonates

Enantiodivergent Formation of C-P Bonds: Synthesis of P-Chiral Phosphines and Methylphosphonate Oligonucleotides

Phosphorus Incorporation (PI, abbreviated Π) reagents for the modular, scalable, and stereospecific synthesis of chiral phosphines and methylphosphonate nucleotides are reported. Synthesized from trans-limonene oxide, this reagent class displays an unexpected reactivity profile and enables access to chemical space distinct from that of the Phosphorus-Sulfur Incorporation reagents previously disclosed. Here, the adaptable phosphorus(V) scaffold enables sequential addition of carbon nucleophiles to produce a variety of enantiopure C-P building blocks. Addition of three carbon nucleophiles to Π, followed by stereospecific reduction, affords useful P-chiral phosphines; introduction instead of a single methyl group reveals the first stereospecific synthesis of methylphosphonate oligonucleotide precursors. While both Π enantiomers are available, only one isomer is required-the order of nucleophile addition controls the absolute stereochemistry of the final product through a unique enantiodivergent design.

Stereocontrolled synthesis of oligonucleotide analogs containing chiral internucleotidic phosphorus atoms

Oligonucleotides, in which one of the two nonbridging oxygen atoms of internucleotidic phosphates is replaced by a different type of atom or a substituent, are useful as therapeutic agents and probes to elucidate mechanisms of enzymatic reactions. The internucleotidic phosphorus atoms of these oligonucleotides are chiral, and the properties of these oligonucleotides are affected by the absolute configuration of the chiral phosphorus atoms. In order to address the issue of chirality, various methods have been developed to synthesize these P-chiral oligonucleotide analogs in a stereocontrolled manner. This critical review focuses on the recent progress in this field (123 references).