Biomedical subjects
Publications and source records attributed to Laurent El Kaim.
The three-component addition of isocyanides to phenol derivatives and aldehydes proceeds easily in methanol to form O-arylated compounds in a new Passerini-type reaction. The key step of the conversion lies in an irreversible Smiles rearrangement of intermediate phenoxyimidate adducts. It represents the first use of a Smiles rearrangement in a Passerini reaction. [reaction: see text]
New heterocyclic scaffolds can be easily prepared by the coupling of heteroaromatic phenols (pyridines, pyrimidines) with carbonyl compounds, amines, and isocyanides. This transformation related to the Ugi reaction probably involves a Smiles rearrangement. The scope of this methodology is further extended by the successful use of heterocyclic thiols to form highly functionalized thioamides.
[reaction: see text] N-Monosubstituted carbamates are cleanly converted to amides under treatment with trialkylaluminum. This reaction involves an aluminum-assisted internal delivery of alkyl groups. It can be applied to new and mild protecting group strategies for alcohols.
Trimethylaluminum addition to N-monoalkyl or N-monoaryl hydrazones followed by aldehyde addition leads to the formation of N-alkylated hydrazones in a new formal Mannich-type process. Addition compounds were also obtained in moderate yields with ketones. The mechanism as well as possible intermediates involved in the reaction are discussed.