Generation of a carbocation via hydride abstraction as a pathway for Csp3–H functionalization has been unexplored due to thermodynamical unfavorability. The Musacchio research group has developed a strategy for achieving a formal hydride abstraction from Csp3–H bonds using visible light. The platform involves a mechanism where an abstractor molecule gets reduced by an excited photocatalyst, and performs hydrogen atom abstraction/transfer (HAT) on a hydrocarbon. This radical then gets oxidized by the photocatalyst and yields a carbocation that can be attacked by a range of nucleophiles. Within the group, we have only explored a specific hydrogen-atom abstractor – the tert-butoxy radical ​​(tBuO•). However, nitrogen-centered radicals have also been known to do HAT. In this project we designed and synthesized four different abstractors that undergo generation of an amidyl radical, a relatively unexplored type of N-centered radical. Each of the four synthesized abstractors generates sterically and electronically different N-centered radicals. We tested the new abstractors on etherification, heterocycle N-alkylation, and cyanation reactions. The new reagents worked with our mechanism and we observed a difference in interactions when varying the functional group on the N radical from a methyl group to a tert-butyl group. Preliminary data suggests the radical sterics can impact regioselectivity. The next steps for this project would be to continue to optimize the reactions tested with the new abstractors to continue to explore the effects of the N-centered amidyl radical.

• This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its website without editorial or peer review.

Creator

• Rivas-Souchet, Ariadna

Publisher

• Worcester Polytechnic Institute

Identifier

• 65441
• E-project-042822-135214

Stichwort

• Photoredox catalysis
• c-h functionalization
• hydrogen atom abstraction
• amidyl radical
• organic chemistry
• hydrogen atom transfer

Advisor

• Musacchio, Patricia Z.

Year

• 2022

Date created

• 2022-04-28

Resource type

• Major Qualifying Project

Major

• Chemistry

Rights statement

• In Copyright