Recent developments in asymmetric Heck type cyclization reactions for constructions of complex molecules

Area of Science:

• Organic Chemistry
• Asymmetric Catalysis
• Synthetic Methodology

Background:

• Intramolecular carbometallation reactions are key for constructing stereocenters in complex molecules.
• Cascade reactions offer efficient strategies for increasing molecular complexity in a single step.

Purpose of the Study:

• To review recent developments (past 5 years) in intramolecular asymmetric Heck reactions and cascade transformations.
• To highlight the use of palladium and nickel catalysts, with a focus on inexpensive nickel complexes.
• To provide perspective on challenges and future directions in asymmetric Heck-type cyclizations.

Main Methods:

• Review of literature on asymmetric Heck reactions and cascade transformations.
• Focus on reactions utilizing palladium and nickel complexes with chiral ligands.
• Analysis of various cascade sequences including Heck/Heck, Heck/nucleophilic trapping, Heck/Tsuji-Trost, Heck/Suzuki-Miyaura, Heck/Sonogashira, and Heck/carbonylation.

Main Results:

• Significant progress has been made using palladium and nickel catalysts for asymmetric transformations.
• Inexpensive nickel complexes have emerged as highly efficient catalysts for several asymmetric reactions.
• The review details numerous examples of constructing complex carbo- and heterocyclic systems.

Conclusions:

• Asymmetric Heck-type cyclizations, especially cascade reactions, are powerful tools for synthesizing complex molecules.
• Nickel catalysis offers a cost-effective and efficient alternative to palladium for these transformations.
• Continued research promises further advancements in catalyst design and reaction scope.