Copper-Catalyzed Regioselective Dehydrogenative Borylation: A Modular Platform Enabling C4-Borylated...

Area of Science:

• Synthetic Organic Chemistry
• Medicinal Chemistry
• Materials Science
• Heterocyclic Chemistry

Background:

• The [2,1]-borazaronaphthalene scaffold is a significant BN-isostere of naphthalene.
• This scaffold holds promise for applications in medicinal and materials chemistry.
• Efficient and regioselective functionalization, particularly at the C4 position, remains a synthetic challenge.

Purpose of the Study:

• To develop a novel method for the direct C4-H borylation of [2,1]-borazaronaphthalenes.
• To achieve regioselective functionalization at the C4 position of the [2,1]-borazaronaphthalene scaffold.
• To expand the synthetic accessibility of diverse 4-boryl-[2,1]-borazaronaphthalene derivatives.

Main Methods:

• Copper-catalyzed, regioselective dehydrogenative borylation reaction.
• Utilized bis(pinacolato)diboron (B₂pin₂) as the boron source.
• Investigated substrate scope and optimized reaction conditions for efficient C4-H borylation.

Main Results:

• Successfully achieved direct C4-H borylation of various [2,1]-borazaronaphthalenes.
• Demonstrated a broad substrate scope, yielding diverse 4-boryl derivatives with high efficiency.
• Gram-scale synthesis and subsequent transformations, including the creation of axially chiral scaffolds, were accomplished.

Conclusions:

• The developed copper-catalyzed borylation offers a versatile and efficient route to C4-functionalized [2,1]-borazaronaphthalenes.
• This method provides a valuable platform for the diversification of BN-heterocycles.
• The resulting 4-boryl derivatives are poised for further exploration in medicinal and materials chemistry.