Visible-Light-Induced Radical Carbo-Cyclization/gem-Diborylation through Triplet Energy Transfer between a Gold Catalyst and Aryl Iodides

2020 ◽  
Vol 142 (23) ◽  
pp. 10485-10493 ◽  
Author(s):  
Lumin Zhang ◽  
Xiaojia Si ◽  
Frank Rominger ◽  
A. Stephen K. Hashmi
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Gold Catalyst ◽  
Triplet Energy ◽  
Aryl Iodides ◽  
Triplet Energy Transfer

scholarly journals Visible Light-Enabled Paternò-Büchi Reaction via Triplet Energy Transfer for the Synthesis of Oxetanes

2020 ◽  
Author(s):  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Uv Light ◽  
Cycloaddition Reaction ◽  
High Energy ◽  
Triplet Energy ◽  
Reaction Conditions ◽  
Triplet Energy Transfer

<div> <p>One of the most efficient ways to synthesize oxetanes is the light-enabled [2+2] cycloaddition reaction of carbonyls and alkenes, referred to as the Paternò-Büchi reaction. The reaction conditions for this transformation typically require the use of high energy UV light to excite the carbonyl, limiting the applications, safety, and scalability. We herein report the development of a visible light-mediated Paternò-Büchi reaction protocol that relies on triplet energy transfer from an iridium-based photocatalyst to the carbonyl substrates. This mode of activation is demonstrated for a variety of aryl glyoxylates and negates the need for both, visible light-absorbing carbonyl starting materials or UV light to enable access to a variety of functionalized oxetanes in up to 99% yield.</p> </div> <br>

scholarly journals Visible Light-Mediated [2+2] Cycloaddition for the Synthesis of Azetidines via Energy Transfer

2018 ◽  
Author(s):  
Marc R. Becker ◽  
Alistair D. Richardson ◽  
Corinna S. Schindler
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Functional Group ◽  
Transfer Mechanism ◽  
Synthetic Methods ◽  
Energy Transfer Mechanism ◽  
Triplet Energy ◽  
Mechanistic Investigations ◽  
Triplet Energy Transfer ◽  
Operational Simplicity

<p>Due to the lack of synthetic methods for their synthesis, azetidines are an underrepresented class of nitrogen-containing heterocycles. Herein, we describe the development of a mild, general protocol for the synthesis of azetidines relying on a visible light-mediated [2+2] cycloaddition between oximes and olefins catalyzed by an iridium photocatalyst. This approach is characterized by its operational simplicity, low catalyst loadings and functional group tolerance. Mechanistic investigations suggest that a triplet energy transfer mechanism is operative.<br></p>

scholarly journals Bodipy–C60 triple hydrogen bonding assemblies as heavy atom-free triplet photosensitizers: preparation and study of the singlet/triplet energy transfer

2015 ◽  
Vol 6 (7) ◽  
pp. 3724-3737 ◽  
Author(s):  
Song Guo ◽  
Liang Xu ◽  
Kejing Xu ◽  
Jianzhang Zhao ◽  
Betül Küçüköz ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Energy Transfer ◽  
Visible Light ◽  
Light Harvesting ◽  
Heavy Atom ◽  
Intersystem Crossing ◽  
Triplet Energy ◽  
Triplet Energy Transfer

Hydrogen bonding-mediated supramolecular triplet photosensitizers with easily interchangeable visible light-harvesting Bodipy modules and the fullerene intersystem crossing module were devised.

scholarly journals Visible Light-Enabled Paternò-Büchi Reaction via Triplet Energy Transfer for the Synthesis of Oxetanes

2020 ◽  
Author(s):  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Uv Light ◽  
Cycloaddition Reaction ◽  
High Energy ◽  
Triplet Energy ◽  
Reaction Conditions ◽  
Triplet Energy Transfer

<div> <p>One of the most efficient ways to synthesize oxetanes is the light-enabled [2+2] cycloaddition reaction of carbonyls and alkenes, referred to as the Paternò-Büchi reaction. The reaction conditions for this transformation typically require the use of high energy UV light to excite the carbonyl, limiting the applications, safety, and scalability. We herein report the development of a visible light-mediated Paternò-Büchi reaction protocol that relies on triplet energy transfer from an iridium-based photocatalyst to the carbonyl substrates. This mode of activation is demonstrated for a variety of aryl glyoxylates and negates the need for both, visible light-absorbing carbonyl starting materials or UV light to enable access to a variety of functionalized oxetanes in up to 99% yield.</p> </div> <br>

scholarly journals Visible Light-Enabled Paternò-Büchi Reaction via Triplet Energy Transfer for the Synthesis of Oxetanes

2020 ◽  
Author(s):  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Uv Light ◽  
Cycloaddition Reaction ◽  
High Energy ◽  
Triplet Energy ◽  
Reaction Conditions ◽  
Triplet Energy Transfer

<div> <p>One of the most efficient ways to synthesize oxetanes is the light-enabled [2+2] cycloaddition reaction of carbonyls and alkenes, referred to as the Paternò-Büchi reaction. The reaction conditions for this transformation typically require the use of high energy UV light to excite the carbonyl, limiting the applications, safety, and scalability. We herein report the development of a visible light-mediated Paternò-Büchi reaction protocol that relies on triplet energy transfer from an iridium-based photocatalyst to the carbonyl substrates. This mode of activation is demonstrated for a variety of aryl glyoxylates and negates the need for both, visible light-absorbing carbonyl starting materials or UV light to enable access to a variety of functionalized oxetanes in up to 99% yield.</p> </div> <br>

scholarly journals Synthesis of Azetidines via Visible Light-Mediated Intermolecular [2+2] Photocycloaddition

2020 ◽  
Author(s):  
Marc R. Becker ◽  
Emily R. Wearing ◽  
Corinna Schindler
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Reactive Intermediates ◽  
Powerful Method ◽  
Triplet Energy ◽  
Mild Conditions ◽  
Broad Scope ◽  
Highly Strained ◽  
Triplet Energy Transfer ◽  
Operational Simplicity

<p>Intermolecular [2+2] photocycloadditions represent a powerful method for the synthesis of highly strained, four-membered rings. While this approach is commonly employed for the synthesis of oxetanes and cyclobutanes, the synthesis of azetidines via intermolecular aza Paternò-Büchi reactions remains highly underdeveloped. Herein we report a visible light-mediated intermolecular aza Paternò-Büchi reaction that utilizes glyoxylate oximes as reactive intermediates activated via triplet energy transfer. This approach is characterized by its operational simplicity, mild conditions and broad scope, and allows for the synthesis of highly functionalized azetidines from readily available precursors.<b></b></p>

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