Switching Selectivity in Borylative Allyl-Allyl Cross-Coupling through Synergistic Catalysis

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Allyl carbonates and allenes are versatile organic synthons.
• Developing enantioselective catalytic methods for constructing complex molecules is crucial in organic synthesis.

Purpose of the Study:

• To report a novel Cu/Pd-catalyzed borylative coupling of allenes with allyl carbonates.
• To achieve regio-, diastereoselective, and enantioselective formation of chiral borylated 1,5-dienes.

Main Methods:

• Synergistic Cu/Pd catalysis was employed.
• Density Functional Theory (DFT) calculations were used to elucidate the reaction mechanism.

Main Results:

• The reaction successfully produced chiral borylated 1,5-dienes with two adjacent tertiary stereocenters.
• Divergent selectivity was observed compared to Cu-only catalysis.
• DFT calculations supported a proposed S_E2' transmetalation and identified the key regio- and diastereodetermining step.

Conclusions:

• The developed Cu/Pd-catalyzed borylative coupling is an effective method for synthesizing complex chiral borylated dienes.
• The study provides mechanistic insights into the synergistic catalytic process.