Leveraging -tosylhydrazones as diazo surrogates for efficient access to pyrazolo-[1,5-]quinazolinone derivatives.

We developed a transition metal-free methodology for the construction of pyrazoloquinazolinone derivatives. The strategy involves a one-pot reaction wherein the -tosylhydrazone and its corresponding diazo derivative are generated , followed by an intramolecular 1,3-dipolar cycloaddition-ring expansion to provide the pyrazolo-[1,5-]quinazolinone motif. This approach enables straightforward access to a diverse range of highly functionalized N-heterocyclic compounds in good yields (up to 92%).

Copper-catalyzed sulfonylation of N-tosylhydrazones followed by a one-pot C-N bond formation.

A new methodology to synthesize sulfonyl-N-phenylaniline derivatives via the trapping of bromo-sulfone derivatives generated from N-tosylhydrazones (NTHs) with amines is described. The reaction proved successful for a wide range of NTHs and amines and tolerated various functional groups on either coupling partner (35 examples). The mechanism was studied, and we showed that the sulfone formation does not follow a radical pathway.

An update on the use of sulfinate derivatives as versatile coupling partners in organic chemistry.

The use of sulfinic acids and their salts continues to be extensively developed in organic chemistry. This is attributable to their dual capacity for acting as nucleophilic or electrophilic reagents, as well as their ease of preparation and stability on storage. This report highlights the research accomplished since 2015 on this topic, updating a previous review published by our team in 2014.