Electron-Deficient Chiral Lactic Acid-Based Hypervalent Iodine Reagents.
Jihan Qurban1, Mohamed Elsherbini1, Thomas Wirth1
1School of Chemistry, Cardiff University , Park Place, Cardiff CF10 3AT, United Kingdom.
The Journal of Organic Chemistry
|July 21, 2017
Summary
New electron-deficient chiral hypervalent iodine reagents were synthesized and demonstrated effective use in oxidative rearrangements. These reagents efficiently convert alkenes to chiral α-aryl ketones with high stereoselectivity.
Area of Science:
- Organic Chemistry
- Asymmetric Synthesis
- Hypervalent Iodine Chemistry
Background:
- Hypervalent iodine reagents are versatile tools in organic synthesis.
- Developing novel chiral reagents is crucial for enantioselective transformations.
- Electron-deficient reagents offer unique reactivity profiles.
Purpose of the Study:
- To synthesize novel electron-deficient chiral hypervalent iodine reagents.
- To investigate the reactivity and stereoselectivity of these reagents in oxidative rearrangements.
- To explore their application in the synthesis of enantiomerically enriched α-aryl ketones.
Main Methods:
- Preparation of novel electron-deficient chiral hypervalent iodine compounds.
- Oxidative rearrangement reactions of various alkenes.
- Analysis of reaction products for yield, reactivity, and enantiomeric excess (ee).
Main Results:
- Successful synthesis of new chiral hypervalent iodine reagents in good yields.
- Demonstrated good reactivity in the oxidative rearrangement of alkenes.
- Achieved high enantiomeric excess in the resulting α-aryl ketone products.
Conclusions:
- The novel electron-deficient chiral hypervalent iodine reagents are effective synthetic tools.
- These reagents enable efficient and highly stereoselective synthesis of α-aryl ketones.
- The developed methodology offers a valuable route to enantiomerically enriched compounds.
Related Concept Videos
Alkyl Halides
20.6K
Structural Properties
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
20.6K
Acid Halides to Ketones: Gilman Reagent
4.1K
Lithium dialkyl cuprate, also known as Gilman reagents, selectively reduces acid halides to ketones. The acid chloride is treated with Gilman reagent at −78 °C in the presence of ether solution to produce a ketone in good yield.
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen...
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen...
4.1K
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
7.7K
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
7.7K
Reactions of Acid Anhydrides
5.3K
The reactions of acid anhydrides are analogous to the reactions of acid chlorides and proceed via a nucleophilic acyl substitution. They only differ in the identity of the leaving group. During an acid chloride reaction, the leaving group is a chloride ion, and the by-product is hydrochloric acid. However, in an acid anhydride reaction, the leaving group is a carboxylate ion, and the by-product is a carboxylic acid.
5.3K
Acid Halides to Alcohols: LiAlH4 Reduction
4.1K
Acid halides are reduced to alcohols in the presence of a strong reducing agent like lithium aluminum hydride.
The mechanism proceeds in three steps. First, the nucleophilic hydride ion attacks the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs as a leaving group, generating an aldehyde. A second nucleophilic attack by the hydride yields an alkoxide ion, which, upon protonation, gives a primary alcohol as...
The mechanism proceeds in three steps. First, the nucleophilic hydride ion attacks the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs as a leaving group, generating an aldehyde. A second nucleophilic attack by the hydride yields an alkoxide ion, which, upon protonation, gives a primary alcohol as...
4.1K
Preparation of Acid Anhydrides
4.1K
One of the methods for preparing symmetrical or unsymmetrical acid anhydrides involves the treatment of acid chlorides with the sodium salt of carboxylic acids. The reaction proceeds via a nucleophilic acyl substitution.
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
4.1K


