Simple, chemoselective hydrogenation with thermodynamic stereocontrol
Kotaro Iwasaki1, Kanny K Wan, Alberto Oppedisano
1Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States.
Journal of the American Chemical Society
|January 17, 2014
Summary
This study introduces a new catalytic hydrogenation method for alkenes, yielding thermodynamically stable alkane products. This approach offers broad functional group compatibility and rapid reaction rates under mild conditions.
Area of Science:
- Organic Chemistry
- Catalysis
- Green Chemistry
Background:
- Hydrogenation of alkenes to thermodynamically favored configurations is challenging, especially when steric hindrance influences hydrogen delivery.
- Existing methods like dissolving metal reduction offer control but suffer from poor functional group tolerance.
- A need exists for efficient hydrogenation techniques compatible with diverse chemical functionalities.
Purpose of the Study:
- To develop a catalytic hydrogenation method for alkenes that selectively produces thermodynamically favored alkane products.
- To achieve broad functional group compatibility in alkene hydrogenation.
- To enable rapid hydrogenation reactions under standard temperature and pressure conditions.
Main Methods:
- Development of a novel catalytic system for alkene hydrogenation.
- Reaction optimization to enhance selectivity for thermodynamic products.
- Testing of the catalytic system's compatibility with various functional groups.
Main Results:
- The catalytic hydrogenation successfully yielded thermodynamically favored alkane products from alkenes.
- The method demonstrated remarkable compatibility with a wide range of functional groups.
- High reaction rates were observed at standard temperature and pressure.
Conclusions:
- A new catalytic hydrogenation method provides access to thermodynamically stable alkane products.
- This method overcomes the limitations of functional group tolerance seen in dissolving metal reductions.
- The developed catalytic system offers a practical and efficient approach for alkene hydrogenation.
Related Concept Videos
02:13Reduction of Alkenes: Catalytic Hydrogenation
12.4K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
12.4K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
2.6K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
2.6K
01:23Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
3.4K
The addition of a hydrogen halide to 1,3-butadiene gives a mixture of 1,2- and 1,4-adducts. Since more substituted alkenes are more stable, the 1,4-adduct is expected to be the major product. However, the product distribution is strongly influenced by temperature; low temperature favors the 1,2-adduct, whereas the 1,4-adduct is predominant at high temperature.
3.4K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
14.2K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
14.2K
02:36Regioselectivity and Stereochemistry of Hydroboration
7.8K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
7.8K
01:28Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
5.6K
Unlike the easy catalytic hydrogenation of an alkene double bond, hydrogenation of a benzene double bond under similar reaction conditions does not take place easily. For example, in the reduction of stilbene, the benzene ring remains unaffected while the alkene bond gets reduced. Hydrogenation of an alkene double bond is exothermic and a favorable process. In contrast, to hydrogenate the first unsaturated bond of benzene, an energy input is needed; that is, the process is endothermic. This is...
5.6K