ortho-C(sp3)–H arylation of aromatic aldehydes using 2-amino-N-methyl-acetamide as a L,L-type transient directing group?

Organic & Biomolecular Chemistry Pub Date: 2023-02-01 DOI: 10.1039/D3OB00024A

Abstract

Pd-catalyzed ortho-C(sp3)–H arylation of aromatic aldehydes using 2-amino-N-methyl-acetamide as a simple, efficient and commercially available L,L-type transient directing group (TDG) is reported. The reaction exhibited excellent substrate compatibility and generated the desired products in moderate-to-high yields up to 78%. Further acid-catalyzed cyclization and dehydrative aromatization were also tested, and furnished some polycyclic aromatic hydrocarbons with excellent yields up to 96%. The X-ray crystal structure of a 2-methylbenzaldehyde ortho-C(sp3)–H palladation intermediate was obtained. Then, a plausible reaction mechanism involving the formation of a [5,6]-fused palladacycle was proposed. This approach offers valuable insights for exploiting novel L,L-type TDGs.

Graphical abstract: ortho-C(sp3)–H arylation of aromatic aldehydes using 2-amino-N-methyl-acetamide as a L,L-type transient directing group
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