Related Experiment Video
Updated: Jun 16, 2026
07:49
Characterizing Lewis Pairs Using Titration Coupled with In Situ Infrared Spectroscopy
Published on: February 20, 2020
9.1K
Asymmetric catalysis by chiral FLPs: A computational mini-review
1Department of Chemistry, National Institute of Technology Silchar, Silchar, India.
Chirality
|April 25, 2024
Summary
Chiral frustrated Lewis pairs (FLPs) enable enantioselective catalysis. Intramolecular FLPs, with optimized Lewis acid-base proximity, efficiently activate H2 and catalyze asymmetric hydrogen transfer reactions.
Area of Science:
- Catalysis
- Organic Chemistry
- Computational Chemistry
Background:
- Frustrated Lewis pairs (FLPs) are formed by sterically hindered Lewis acids (LAs) and Lewis bases (LBs) that cannot form classical adducts.
- Chiral FLPs have emerged as a growing field in enantioselective catalysis over the past 16 years.
- Chiral LAs play a crucial role in the hydrogen transfer step, dictating enantioselectivity in imine reduction.
Purpose of the Study:
- To review computational investigations of chiral LAs and LBs in catalysis.
- To discuss the efficiency of intramolecular FLPs in enantioselective catalysis.
- To highlight the role of noncovalent interactions in stabilizing activated species.
Main Methods:
- Computational investigations of chiral Lewis acids and Lewis bases.
- Analysis of hydrogen transfer mechanisms in imine reduction.
- Examination of intramolecular FLP systems with chiral scaffolds.
Main Results:
- Chiral LAs are key to achieving enantioselectivity via hydrogen transfer.
- Borohydride intermediates adopt conformations stabilized by C-H···π and π···π interactions.
- Intramolecular FLPs demonstrate high efficiency due to optimal LA-LB distances, preventing substrate adduct formation.
Conclusions:
- Intramolecular FLPs are highly efficient for enantioselective catalysis.
- The design of FLPs with specific chiral scaffolds is critical for catalytic performance.
- Computational studies provide valuable insights into FLP reaction mechanisms and stability.
Related Concept Videos
02:30Chirality in Nature
Chirality is the most intriguing yet essential facet of nature, governing life’s biochemical processes and precision. It can be observed from a snail shell pattern in a macroscopic world to an amino acid, the minutest building block of life. Most of the snails around the world have right-coiled shells because of the intrinsic chirality in their genes. All the amino acids present in the human body exist in an enantiomerically pure state, except for glycine - the sole achiral amino acid. The...
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
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...
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
02:25Chirality
Chirality is a term that describes the lack of mirror symmetry in an object. In other words, chiral objects cannot be superposed on their mirror images. For example, our feet are chiral, as the mirror image of the left foot, the right foot, cannot be superposed on the left foot.
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
02:25Molecules with Multiple Chiral Centers
Molecules that possess multiple chiral centers can afford a large number of stereoisomers. For instance, while some molecules like 2-butanol have one chiral center, defined as a tetrahedral carbon atom with four different substituents attached, several molecules like butane-2,3-diol have multiple chiral centers. A simple formula to predict the number of stereoisomers possible for a molecule with n chiral centers is 2n. However, there can be a lower number where some of the stereoisomers are...
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...