Chiral phosphoramidite auxiliaries and methods of their use
Disclosed are chiral phosphoramidite auxiliary compositions for diastereoselective synthesis of stereochemically enriched oligonucleotides, and nucleoside phosphoramidite compounds comprising the same. Exemplary structures of the chiral phosphoramidite auxiliary compositions include Formulas (IA) and (IB).
1. A compound of formula (IIIA) or (IIIB):
wherein
is a single carbon-carbon bond or a double carbon-carbon bond;
A is an optionally substituted C 1-12 alkyl, optionally substituted C 3-10 cycloalkyl, optionally substituted C 3-10 cycloalkyl-C 1-6 -alkyl, optionally substituted C 1-9 heterocyclyl, optionally substituted C 1-9 heterocyclyl-C 1-6 -alkyl, sugar analogue, nucleoside, nucleotide, or oligonucleotide;
each of R 1 and R 2 is independently an optionally substituted C 1-6 alkyl or optionally substituted C 6-10 aryl, or R 1 and R 2 , together with the atoms to which each is attached, combine to form an optionally substituted 5- to 8-membered ring; and
each of R 3 and R 4 is independently H, optionally substituted C 1-6 alkyl, or optionally substituted C 6-10 aryl.
2. The compound of claim 1 , wherein R 1 and R 2 , together with the atoms to which each is attached, combine to form an optionally substituted 5- to 8-membered ring.
3. The compound of claim 1 , wherein the compound is of the following structure:
4. A nucleoside phosphoramidite comprising a sugar bonded to a nucleobase and to a phosphoramidite of the following structure:
wherein
is a single carbon-carbon bond or a double carbon-carbon bond;
each of R 1 and R 2 is independently an optionally substituted C 1-6 alkyl or optionally substituted C 6-10 aryl, or R 1 and R 2 , together with the atoms to which each is attached, combine to form an optionally substituted 5- to 8-membered ring; and
each of R 3 and R 4 is independently H, optionally substituted C 1-6 alkyl, or optionally substituted C 6-10 aryl.
5. The nucleoside phosphoramidite of claim 4 , wherein the nucleoside phosphoramidite is of the following structure:
wherein
B 1 is a nucleobase;
Y 1 is H or C 1-6 alkyl;
R 5 is H, O-protected hydroxyl, optionally substituted C 1-6 alkoxy, or halogen; and
R 6 is a hydroxyl protecting group.
6. The nucleoside phosphoramidite of any one of claims 5 , wherein R 6 is dimethoxytrityl.
7. The nucleoside phosphoramidite of claim 4 , wherein R 1 and R 2 , together with the atoms to which each is attached, combine to form an optionally substituted 5- to 8-membered ring.
8. The nucleoside phosphoramidite of claim 4 , wherein the phosphoramidite is of the following structure:
9. A method of preparing a composition comprising an oligonucleotide comprising a stereochemically enriched internucleoside phosphorothioate, the method comprising (i) reacting the nucleoside phosphoramidite of claim 4 with a coupling activator and a nucleoside comprising a 5′-hydroxyl or an oligonucleotide comprising a 5′-hydroxyl, (ii) reacting with an electrophilic source of acyl, and (iii) reacting with a sulfurizing agent to produce the oligonucleotide comprising a stereochemically enriched internucleoside phosphorothioate triester.
10. A method of preparing the nucleoside phosphoramidite comprising a sugar bonded to a nucleobase and phosphoramidite of the following structure:
wherein
is a single carbon-carbon bond or a double carbon-carbon bond;
each of R 1 and R 2 is independently an optionally substituted C 1-6 alkyl or optionally substituted C 6-10 aryl, or R 1 and R 2 , together with the atoms to which each is attached, combine to form an optionally substituted 5- to 8-membered ring; and
each of R 3 and R 4 is independently H, optionally substituted C 1-6 alkyl, or optionally substituted C 6-10 aryl;
the method comprising reacting a sugar bonded to a nucleobase with a compound of formula (VIIIA) or (VIIIB):
wherein
X is a halogen or pseudohalogen.
11. An oligonucleotide comprising one or more internucleoside groups independently selected from the group consisting of linkers of formulas (XIA), (XIB), (XIIA) and (XIIB):
where
is a single carbon-carbon bond or a double carbon-carbon bond;
each of R 1 and R 2 is independently an optionally substituted C 1-6 alkyl or optionally substituted C 6-10 aryl, or R 1 and R 2 , together with the atoms to which each is attached, combine to form an optionally substituted 5- to 8-membered ring;
each of R 3 and R 4 is independently H, optionally substituted C 1-6 alkyl, or optionally substituted C 6-10 aryl; and
R 7 is acyl.
12. The compound of claim 1 , wherein each of R 3 and R 4 is independently H.
13. The compound of claim 2 , wherein the optionally substituted 5- to 8-membered ring is an optionally substituted 6-membered carbocyclic ring.
14. The nucleoside phosphoramidite of claim 4 , wherein each of R 3 and R 4 is independently H.
15. The nucleoside phosphoramidite of claim 7 , wherein the optionally substituted 5- to 8-membered ring is an optionally substituted 6-membered carbocyclic ring.
16. The method of claim 10 , wherein the optionally substituted 5- to 8-membered ring is an optionally substituted 6-membered carbocyclic ring.
17. The method of claim 10 , wherein each of R 3 and R 4 is independently H.
18. The oligonucleotide of claim 11 , wherein the substituted 5- to 8-membered ring is substituted 6-membered carbocyclic ring.
19. The oligonucleotide of claim 11 , comprising one or more internucleoside groups independently selected from the group consisting of linkers of formulas (XIIA) and (XIIB):
20. The oligonucleotide of claim 11 , comprising one or more internucleoside groups independently selected from the group consisting of linkers of formulas (XIA) and (XIB):