Iridium-catalyzed enantioselective allylic vinylation

Area of Science:

• Organometallic Chemistry
• Asymmetric Catalysis
• Synthetic Organic Chemistry

Background:

• Vinyl trifluoroborates are versatile synthetic reagents.
• Asymmetric catalysis is crucial for synthesizing enantiomerically pure compounds.
• Developing efficient methods for 1,4-diene and triene synthesis is important.

Purpose of the Study:

• To report the first iridium-catalyzed asymmetric substitution reaction with vinyl trifluoroborates.
• To develop a method for the enantioselective synthesis of 1,4-dienes and trienes.
• To demonstrate the utility of this method for natural product synthesis.

Main Methods:

• Utilizing an iridium-(P,olefin) complex as the catalyst.
• Reacting branched, racemic allylic alcohols with potassium alkenyltrifluoroborates.
• Employing asymmetric substitution reaction conditions.

Main Results:

• Achieved high site selectivity in the substitution reaction.
• Obtained excellent enantioselectivity, up to 99%.
• Successfully synthesized various 1,4-dienes and trienes, including (-)-nyasol and (-)-hinokiresinol.

Conclusions:

• The developed Ir-catalyzed reaction is the first of its kind with vinyl trifluoroborates.
• This method provides rapid access to enantiomerically enriched dienes and trienes.
• The methodology is applicable to the synthesis of biologically active natural products.