Rapid Access to Conjugated Z,Z,Z-Trienes.

Area of Science:

• Organic Synthesis
• Reaction Mechanisms
• Synthetic Chemistry

Background:

• Intercepting reactions offer novel pathways in organic synthesis.
• Harnessing reactive intermediates allows access to complex molecular structures.
• Conventional methods face limitations in synthesizing specific functionalities.

Purpose of the Study:

• To develop a new protocol for the nucleophile-intercepted Beckmann fragmentation reaction (NuBFr).
• To synthesize novel conjugated Z,Z,Z-trienecarbonitrile derivatives.
• To explore unusual reactivities and complex molecular architectures.

Main Methods:

• Utilized tropone oxime tosylate as a precursor.
• Employed a diverse set of nucleophiles generated in situ (alcohols, phenols, thiols, alkynes).
• Applied strong bases to facilitate the reaction.

Main Results:

• Successfully synthesized a library of novel conjugated Z,Z,Z-trienecarbonitrile derivatives.
• Achieved rapid access to the rare Z,Z,Z-triene motif.
• Computational studies suggest a bicyclic azirine intermediate.

Conclusions:

• The NuBFr reaction provides efficient access to conjugated Z,Z,Z-trienecarbonitriles.
• These derivatives can undergo a unique electrocyclization cascade to form trisubstituted olefins.
• This work expands the scope of unusual reactivities in organic synthesis.