Stable borane reagents and methods for their use
View Patent ↗The invention provides methods for storing boranes (e.g. B-allyldiisopinocampheylborane). The invention also provides stable compositions comprising boranes, as well as methods for carrying out allylboration at high temperature and/or in the presence of water.
1. A method for stabilizing a borane comprising storing a borane of formula (I):
wherein R 1 , R 2 , and R 3 are each independently selected from H, (C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, aryl, and aryl(C 1 -C 6 )alkyl; and each Ipc is isopinocampheyl; wherein the borane is stored in the presence of a solvent and the solvent comprises a (C 5 -C 12 ) hydrocarbon, a (C 4 -C 10 ) ether, or a halogenated (C 1 -C 10 ) hydrocarbon, or a mixture thereof under conditions such that less than 10% of the borane by weight decomposes after three days.
2. The method of claim 1 wherein the borane is B-allyldiisopinocampheylborane.
3. The method of claim 1 wherein the solvent comprises pentane.
4. The method of claim 1 wherein the solvent comprises dioxane.
5. The method of claim 1 wherein less than about 5% of the borane by weight decomposes after thirty days.
6. The method of claim 1 wherein the borane is stored in an inert environment.
7. The method of claim 6 wherein the inert environment comprises argon or nitrogen gas.
8. The method of claim 6 wherein the borane is stored in an air-tight vial or air-tight ampoule.
9. The method of claim 1 wherein the borane is stored below room temperature.
10. The method of claim 1 wherein the borane is stored at room temperature.
11. A composition comprising dioxane and a borane of formula (I):
wherein R 1 , R 2 , and R 3 are each independently selected from H, (C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, aryl, and aryl(C 1 -C 6 )alkyl; and each Ipc is isopinocampheyl.
12. The composition of claim 11 which is a solid.
13. A kit comprising 1) packaging material, and 2) a borane of formula (I) that is at least 3 days old:
wherein R 1 , R 2 , and R 3 are each independently selected from H, (C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, aryl, and aryl(C 1 -C 6 )alkyl; and each Ipc is isopinocampheyl wherein the borane is stored in the presence of a solvent and the solvent comprises a (C 5 -C 12 ) hydrocarbon, a (C 4 -C 10 ) ether, or a halogenated (C 1 -C 10 ) hydrocarbon, or a mixture thereof.
14. The kit of claim 13 wherein the borane is stored in a solvent that comprises dioxane or pentane, or a mixture thereof.
15. The method of claim 1 wherein the solvent comprises benzene.
16. The kit of claim 13 wherein the borane is stored in a solvent that comprises benzene.
17. A composition comprising pentane and a borane of formula (I):
wherein R 1 , R 2 , and R 3 are each independently selected from H, (C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, aryl, and aryl(C 1 -C 6 )alkyl; and each Ipc is isopinocampheyl.
18. A composition comprising a borane of formula (I):
and further comprising a solvent wherein the solvent comprises a (C 5 -C 12 ) hydrocarbon, a (C 4 -C 10 ) ether, or a halogenated (C 1 -C 10 ) hydrocarbon, or a mixture thereof wherein R 1 , R 2 , and R 3 are each independently selected from H, (C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, aryl, and aryl(C 1 -C 6 )alkyl and each Ipc is isopinocampheyl.