Millisecond Aliphatic Iodonium-Claisen Rearrangement Enabling Dual Functionalization of Alkenyl Iodanes

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Claisen rearrangements have evolved by expanding the central atom beyond oxygen.
• This expansion has redefined substrates, selectivity control, and product diversity in organic synthesis.

Purpose of the Study:

• To report a new aliphatic iodonium Claisen rearrangement utilizing alkenyl iodanes.
• To demonstrate the reaction's efficiency, broad substrate scope, and potential for dual functionalization.

Main Methods:

• Employing iodine(III) moieties to replace the classic oxygen center in Claisen rearrangements.
• Investigating the rearrangement of allyl alkenyl iodonium species with various nucleophiles at low temperatures.
• Conducting mechanistic studies to understand reaction kinetics and the role of the hypervalent iodine center.

Main Results:

• The aliphatic iodonium Claisen rearrangement proceeds rapidly (<0.1 s) at -78 °C.
• The reaction accommodates a diverse range of nucleophiles, including silanes, stannyl nitriles, azides, acetates, and phenols.
• Rearrangement intermediates can be intercepted, enabling dual functionalization of alkenyl iodanes.

Conclusions:

• Hypervalent iodine enables a highly efficient and versatile Claisen rearrangement.
• The trans influence of the iodine(III) center plays a crucial role in reaction kinetics and partner assembly.
• This method significantly expands the scope and utility of Claisen rearrangements in organic synthesis.