Alkynyl Phenyl Selenides as Intermediates in the Metal‐Free Cyclisation of N‐Tosyl Homopropargyl Amides to γ‐Lactams

In this work, we present an efficient Brønsted acid-catalysed intramolecular hydroamination reaction of homopropargyl N-tosyl amides to produce synthetically useful substituted γ-lactams through the corresponding alkynyl phenyl selenide intermediates. Our focus on optimising the cyclisation protocol under flow conditions has led to a significant enhancement in efficiency, thereby reducing the time and resources required for the process. DFT calculations of the reaction mechanism for the catalytic transformation of a model alkynyl phenyl selenide were also conducted.