Hydrogenation of Borylated Arenes

Area of Science:

• Organometallic Chemistry
• Catalysis
• Organic Synthesis

Background:

• Aryl boronic acids are common synthetic precursors.
• Saturated cyclic boronates are valuable but difficult to access.
• Existing methods for synthesizing saturated boronates are limited.

Purpose of the Study:

• To develop a novel method for synthesizing saturated, borylated carbo- and heterocycles.
• To utilize abundant aryl boronic acids as starting materials.
• To establish a cis-selective hydrogenation catalyzed by rhodium cyclic (alkyl)(amino)carbene (Rh-CAAC).

Main Methods:

• Employing a rhodium cyclic (alkyl)(amino)carbene (Rh-CAAC) catalyst.
• Performing a cis-selective hydrogenation reaction.
• Utilizing various aryl boronic acids and their derivatives with diverse boron-protecting groups.

Main Results:

• Achieved direct access to a broad scope of saturated, borylated carbo- and heterocycles.
• Demonstrated tolerance to a variety of boron-protecting groups.
• Showcased the utility of the synthesized saturated cyclic building blocks through post-functionalization of the boron group.

Conclusions:

• The reported Rh-CAAC catalyzed cis-selective hydrogenation offers a strategic and efficient route to valuable saturated borylated cyclic compounds.
• This method overcomes limitations of existing synthetic approaches for these important building blocks.
• The synthesized products are versatile and amenable to further chemical transformations.