Asymmetric Ylide Reactions in Organic Synthesis

Asymmetric ylide reactions exploit carbanion–heteroatom bonded intermediates to forge carbon–carbon and carbon–heteroatom bonds with high stereocontrol. Sulfur, phosphorus and ammonium ylides serve as versatile one-carbon synthons for epoxidation, cyclopropanation, aziridination and olefination. Chiral catalysts or auxiliaries guide the approach of ylides to electrophilic partners—such as aldehydes, ketones or imines—yielding three-membered rings or alkenes in enantioenriched form. These methods have matured into practical protocols that tolerate diverse functional groups, enabling streamlined access to drug candidates, natural products and complex molecular scaffolds. Key developments include organocatalytic asymmetric epoxidations using chiral sulfides, transition metal-promoted ylide cycloisomerisations and stereodivergent olefinations that challenge traditional reactivity paradigms. Together, these transformations underscore the global significance of ylide chemistry for constructing stereodefined architectures under mild conditions and with broad substrate scope.

Research from Nature Portfolio

Recent studies have demonstrated formal enantioselective one-carbon insertion into aromatic carbon–nitrogen bonds via chiral sulfur ylide-mediated aziridination and subsequent rearrangement. This approach converts abundant anilines into chiral α-branched benzylic amines through an oxidative dearomatisation–ylide addition sequence. Careful design of the chiral sulfide enables high enantioselectivities, while the rearrangement step furnishes structurally diverse amines under operationally simple conditions. The methodology highlights the power of asymmetric ylide intermediates to introduce stereocentres directly into traditionally inert aromatic systems.

Asymmetric Ylide Reactions in Organic Synthesis publication trend

The graph below shows the total number of articles in asymmetric ylide reactions in organic synthesis across all publications each year (not limited to Nature Index journals).

Technical terms

Ylide: A neutral molecule containing adjacent positively and negatively charged atoms, often used as a nucleophilic one-carbon synthon.

Enantioselectivity: The preference of a reaction to form one enantiomer over its mirror image.

Epoxidation: Conversion of an alkene into a three-membered cyclic ether (an epoxide).

Aziridination: Formation of a three-membered cyclic amine (aziridine) via nitrene or ylide intermediates.

Cyclopropanation: Generation of a three-membered cyclopropane ring from alkenes and carbene or ylide precursors.

Zwitterionic betaine intermediate: A transient species bearing both positive and negative charges, formed when a ylide adds to an electrophile before cyclisation.

References

1. Application of Enantioselective Sulfur Ylide Epoxidation to a Short Asymmetric Synthesis of Bedaquiline, a Potent Anti-Tuberculosis Drug. Organic Letters (2023).
2. Conversion of anilines to chiral benzylic amines via formal one-carbon insertion into aromatic C–N bonds. Nature Communications (2020).
3. Direct Stereodivergent Olefination of Carbonyl Compounds with Sulfur Ylides. Journal of the American Chemical Society (2022).
4. Recent Developments in Stereoselective Reactions of Sulfonium Ylides. Organics (2022).