Original Article:
Cobalt-Catalyzed Alkoxycarbonylation of Epoxides to β-Hydroxyesters
Jian-Xing Xu, et al.
J. Org. Chem. 2019, 84, 16, 9907-9912.
10.1021/acs.joc.9b01007
Cobalt bromide (CoBr2) is a simple, inexpensive, and air-stable catalyst commonly used to catalyze various organic synthesis reactions, such as C-metal, C-heteroatom and C-C bond formation, addition of unsaturated bonds, ring oxidation, polymerization, redox, and carbonylation. In this work, the authors developed a novel and practical catalytic system for the carbonylation synthesis of β-hydroxyesters. It is worth mentioning that this strategy provides the possibility for the reuse of cobalt catalysts by adding a catalytic amount of manganese.
The catalytic system was tested for a variety of epoxides, including terminal epoxides bearing alkyl, alkenyl, alkyl-aryl, glycidyl, and heteroatom groups. It was shown that these epoxides were converted to the corresponding β-hydroxy esters in moderate to excellent yields, to name a few:
1. 3-Phenyl and 3-benzyl substituted epoxy give the desired β-hydroxyester 3f and 3g in excellent yields (91% and 94%) with this catalytic system.
2. The reaction was more facile for epoxides with alkyl substitutions at 3-positions, which were transformed into the desired products 3a-e in high yields (83-94%).
3. 4-(Oxiran-2-yl) butyl acetate (1i) gave the ethyl 3, 7-dihydroxyheptanoate (3i) in 76% yield after alkoxycarbonylation and alcoholysis.
 bromide hydrate.png)
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM85017772 | Cobalt(II) bromide hydrate |  |
85017-77-2 | Price |
