Aerobic Allylic Amination Catalyzed by a Pd(OAc)₂/P(OPh)₃ System with Low Catalyst Loading.

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Tsuji-Trost allylic amination is a crucial reaction in organic synthesis.
• Developing efficient and selective catalytic systems remains an active area of research.
• The use of alternative electrophiles and aerobic conditions presents opportunities for greener synthesis.

Purpose of the Study:

• To develop a novel palladium-catalyzed Tsuji-Trost-type allylic amination protocol.
• To investigate the efficacy of allylic phosphates as electrophiles in this reaction.
• To achieve high catalytic efficiency using a minimal amount of palladium catalyst under aerobic conditions.

Main Methods:

• Utilized a palladium(II) acetate (Pd(OAc)2) and triphenyl phosphite (P(OPh)3) catalyst system.
• Employed Tsuji-Trost-type allylic amination with allylic phosphates as electrophiles.
• Conducted reactions under aerobic conditions to promote sustainability.

Main Results:

• Successfully catalyzed the amination of both aromatic and aliphatic secondary amines.
• Achieved high yields of allylic amines using a low catalyst loading (0.02 mol % Pd).
• Demonstrated that allylic phosphates are superior electrophiles compared to allylic acetate and carbonate.

Conclusions:

• The Pd(OAc)2/P(OPh)3 system effectively catalyzes allylic amination with allylic phosphates.
• The developed method offers an efficient route to allylic amines under mild, aerobic conditions.
• Mechanistic studies suggest an in situ generated Pd(0) complex, Pd[P(OPh)3]3, is the active catalytic species.