Event Title

Visible Light-Promoted Additions of Potassium Organotrifluoroborates to Imines

Poster Number

004

Faculty Mentor

James M. Hanna Jr., Ph.D.

College

College of Arts and Sciences

Department

Department of Chemistry, Physics, and Geology

Location

Rutledge

Start Date

20-4-2018 12:00 PM

End Date

20-4-2018 2:00 PM

Description

Recently, the use of visible light combined with a suitable photocatalyst to promote key bond-forming steps in organic synthesis has emerged as a viable strategy to achieve a number of important synthetic transformations. Visible-light photochemistry has several advantages over traditional ultraviolet (UV) radiation-promoted organic photochemistry. For example, many applications of UV photochemistry require quartz vessels to ensure the radiation can penetrate the vessel, and make use of wavelengths that can electronically excite organic substrates, potentially leading to unwanted side reactions. In contrast, visible light passes through ordinary glass, and small organic substrates do not typically absorb wavelengths in the visible range. The photocatalyst involved is often a ruthenium or iridium polypyridyl complex, which absorbs light in the visible range to give a relatively long-lived excited state, which can engage organic substrates in a series of single-electron-transfer (SET) events. The organic radicals thus generated participate in downstream reactions, leading to the final product(s). The ability of these photocatalysts to function as both SET oxidants and reductants within the same cycle suggests the possibility of a selective, redox-neutral, radical generation and cross-coupling strategy, where radicals derived from both an acceptor (A) and a donor (D) would engage in productive cross-coupling to form a product (A-D). Our group has successfully employed this approach for the formal 1,2-addition of potassium alkyltrifluoroborates to aryl aldimines in moderate to good yields.

Previously Presented/Performed?

Southeast Regional Meeting of the American Chemical Society (SERMACS), Charlotte, North Carolina, November 2017

Grant Support?

Supported by the Donors of the American Chemical Society Petroleum Research Fund and by an SC INBRE grant from the National Institute of General Medical Sciences

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Apr 20th, 12:00 PM Apr 20th, 2:00 PM

Visible Light-Promoted Additions of Potassium Organotrifluoroborates to Imines

Rutledge

Recently, the use of visible light combined with a suitable photocatalyst to promote key bond-forming steps in organic synthesis has emerged as a viable strategy to achieve a number of important synthetic transformations. Visible-light photochemistry has several advantages over traditional ultraviolet (UV) radiation-promoted organic photochemistry. For example, many applications of UV photochemistry require quartz vessels to ensure the radiation can penetrate the vessel, and make use of wavelengths that can electronically excite organic substrates, potentially leading to unwanted side reactions. In contrast, visible light passes through ordinary glass, and small organic substrates do not typically absorb wavelengths in the visible range. The photocatalyst involved is often a ruthenium or iridium polypyridyl complex, which absorbs light in the visible range to give a relatively long-lived excited state, which can engage organic substrates in a series of single-electron-transfer (SET) events. The organic radicals thus generated participate in downstream reactions, leading to the final product(s). The ability of these photocatalysts to function as both SET oxidants and reductants within the same cycle suggests the possibility of a selective, redox-neutral, radical generation and cross-coupling strategy, where radicals derived from both an acceptor (A) and a donor (D) would engage in productive cross-coupling to form a product (A-D). Our group has successfully employed this approach for the formal 1,2-addition of potassium alkyltrifluoroborates to aryl aldimines in moderate to good yields.