ALKYLARYLATION OF UNACTIVATED ALKENES IN ALKENYL KETIMINES AND AMINES
Open Access
- Author:
- Aryal, Vivek
- Graduate Program:
- Chemistry
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 07, 2024
- Committee Members:
- Ramesh Giri, Chair & Dissertation Advisor
Eric Nacsa, Major Field Member
Emily Weinert, Outside Unit & Field Member
Ayusman Sen, Major Field Member
Kenneth Knappenberger, Program Head/Chair - Keywords:
- Unactivated alkenes
Coordinating groups
Alkylarylation
Ni-catalysis
Alkylorganozinc reagents - Abstract:
- Three component alkene 1,2-dicarbofunctionalization is an efficient synthetic strategy for generating complex carbon framework in a concise manner. This method allows an alkene to combine with electrophiles and/or nucleophiles in the presence of a suitable metal catalyst. However, the b-H elimination from [M]-C(sp3) species generated in situ as reaction intermediates remains a major challenge to overcome. Over the past several years, unactivated alkenes have been functionalized using a suitable coordinating group tethered to an alkene that offers a stable metallacycle which slows down β-H elimination. As such various functional groups like imine, ester, carboxylic acid, amide, and ketone have been explored in incorporating C(sp2) groups into alkenes. Unlike C(sp2) groups, methods to install C(sp3) groups are more challenging and, therefore, less explored. The limited published works rely on utilizing alkyl electrophiles, such as alkyl halides or pseudohalides, which undergo radical pathway and circumvent β-H elimination pathway. Unlike alkyl electrophiles, alkyl nucleophiles, like alkyl organometals, have been less explored since they introduce additional β-H’s, further complicating the reaction. This dissertation outlines the development of two new platforms for functionalizing unactivated alkenes utilizing alkylzinc halides as C(sp3) sources. Herein, we implement removable imines and unmodified simple amines as coordinating groups. The second research chapter (Chapter 2) describes imine coordinated Ni-catalyzed regioselective 1,2-alkylarylation of γ,δ-alkenylketimines using alkyl organozinc halides as nucleophiles and aryl halides as electorphiles giving γ,δ-substituted ketones branched in a regioselective the work related to the use of imine as a coordinating group. From the mechanistic study, it was observed that electron deficient alkene ligands play a crucial role in this reaction. Similarly, the second research chapter deals with the use of simple amines as a coordinating group and under Ni-catalysis it furnishes 1,2-alkylarylated amines as the products. From the mechanistic study, it was observed that the reaction works well with cooperative effect of electron deficient alkene ligands and nitriles has been performed.