Ionic Liquid Mediated Triple Catalysis for Alkylation and Methylation of Acyl Chlorides with Mechanistic Insight

Here we report a seminal triple catalysis strategy with the assistance of catalytic ionic liquid. DFT calculations reveal the detailed effect of ionic liquid in this triple catalysis mediated C(sp(3))-H functionalizations and a very different mechanism has been established in contrast to all previous dual catalysis research. Based on it, direct coupling between acyl chlorides and very strong or polar C(sp(3))-H bonds has been realized in high yields as well as unexpected methylation of acyl chlorides first using just 1.2 equivalent tetramethylsilane as methyl source via successive C(sp(3))-H and C(sp(3))-Si cleavage. One pot methylation strategy has been developed in this research. This is the first report of that ionic liquid is used for very strong C(sp(3))-H bonds functionalization and the first report of that tetramethylsilane is used as methyl source. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

We report a seminal triple catalysis strategy assisted by catalytic ionic liquid. DFT calculations reveal the detailed effect of the ionic liquid in the C(sp(3))-H functionalizations mediated by this triple catalysis and establish a very different mechanism compared to previous dual catalysis research. Using this mechanism, direct coupling between acyl chlorides and very strong or polar C(sp(3))-H bonds has been achieved with high yields, along with unexpected methylation of acyl chlorides using tetramethylsilane as the methyl source. This research develops a one pot methylation strategy. It is the first report of using an ionic liquid for the functionalization of very strong C(sp(3))-H bonds and the first report of using tetramethylsilane as a methyl source.