Ni(0) catalysts
Provided herein are nickel(O) catalysts that are stable when exposed to air and can be used to catalyze the formation of a C—C, C—O, or C—N bond.
1. A catalyst having a structure of formula (I) or (II):
wherein
the dashed line is an optional double bond;
each R 1 is independently selected from the group consisting of H, C 1-8 alkyl and C 1-2 alkylenearyl;
each R 2 is independently selected from the group consisting of H, halo, C 1-3 alkyl, and aryl, or both R 2 together with the carbons to which they are attached form a 6-membered ring;
each R 3 is the same and is H, C 1-4 alkyl, or aryl;
each R 4 is the same and is C 1-6 alkyl, C 0-2 alkylene-aryl or C 0-2 alkylene-C 2-8 alkene;
each R 5 is the same and is H, C 1-6 alkyl, aryl, CO 2 C 0-2 alkylene-aryl, CO 2 C 0-2 alkylene-C 2-8 alkene, CO 2 iPr or CO 2 tBu; and
each R 6 is the same and is H, C 1-6 alkyl, C 1-6 alkoxy, or O-aryl, with the proviso that at least one of R 1 and R 6 is not H.
2. The catalyst of claim 1 , wherein the dashed line represents a double bond.
3. The catalyst of claim 1 , wherein each R 1 is the same.
4. The catalyst of claim 1 , wherein R 1 is selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, t-butyl, pentyl, 3-pentyl, and diphenylmethyl.
5. The catalyst of claim 1 , wherein each R 2 is selected from H, chloro, and methyl, or wherein both R 2 together with the carbons to which they are attached form a 6-membered ring.
6. The catalyst of claim 1 , wherein R 3 is aryl.
7. The catalyst of claim 1 , wherein R 3 is C 1-4 alkyl or H.
8. The catalyst of claim 1 , wherein R 4 is C 0-2 alkylene-aryl.
9. The catalyst of claim 1 , wherein R 4 is C 0-2 alkylene-C 2-8 alkene.
10. The catalyst of claim 1 , wherein R 4 is C 2-6 alkyl.
11. The catalyst of claim 1 , wherein R 5 is H.
12. The catalyst of claim 1 , wherein R 5 is C 1-6 alkyl.
13. The catalyst of claim 1 , wherein R 5 is aryl.
14. The catalyst of claim 1 , wherein R 5 is CO 2 C 0-2 alkylene-aryl, or CO 2 C 0-2 alkylene-C 2-8 alkene.
15. The catalyst of claim 1 , wherein R 6 is H or C 1-6 alkyl.
16. The catalyst of claim 1 , wherein R 6 is C 1-6 alkoxy.
17. The catalyst of claim 1 , wherein R 6 is O-aryl.
18. A catalyst selected from the group consisting of
wherein Tol is
Ph(OMe) is
Ph(Me) 3 is
and Ph(CO 2 Me) is
19. A catalyst having a structure of formula (I) or (II):
wherein
the dashed line is an optional double bond;
each R 1 is independently selected from the group consisting of H, C 1-8 alkyl and C 1-2 alkylenearyl;
each R 2 is independently selected from the group consisting of H, halo, C 1-3 alkyl, and aryl, or both R 2 together with the carbons to which they are attached form a 6-membered ring;
each R 3 is the same and is H, C 1-4 alkyl, or aryl;
each R 4 is the same and is C 1-6 alkyl, C 0-2 alkylene-aryl or C 0-2 alkylene-C 2-8 alkene;
each R 5 is H; and
each R 6 is the same and is H, C 1-6 alkyl, C 1-6 alkoxy, or O-aryl, with the proviso that at least one of R 1 and R 6 is not H.
20. The catalyst of claim 19 , wherein R 4 is C 0-2 alkylene-aryl.