Forming Stereogenic Centers in Acyclic Systems from Alkynes
Roxane Vabre1, Biana Island1, Claudia J Diehl2
1The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000 (Israel).
This study introduces a novel carbometalation/zinc homologation method for creating complex molecules. The reaction efficiently forms multiple carbon-carbon bonds and stereocenters in a single step from simple alkynes.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
Background:
- Carbometalation and zinc homologation are key reactions in organic synthesis.
- Developing efficient methods for creating complex acyclic molecules with multiple stereocenters is crucial.
Purpose of the Study:
- To develop a novel, single-pot method for synthesizing functionalized acyclic compounds.
- To investigate the stereochemical outcomes of reactions involving α-heterosubstituted aldehydes and imines.
Main Methods:
- A combined carbometalation/zinc homologation strategy was employed.
- The reaction sequence involved subsequent coupling with α-heterosubstituted aldehydes and imines.
Main Results:
- The reaction proceeds via a chair-like transition structure, with substituents favoring pseudo-axial positions.
- A chelated intermediate was observed, influencing face differentiation in allylation.
- The method successfully generated products with three new carbon-carbon bonds and 2-3 stereogenic centers, including a quaternary center.
Conclusions:
- This one-pot procedure offers an efficient route to complex acyclic molecules from simple alkynes.
- The observed stereochemical control provides valuable insights into the reaction mechanism.
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