We describe a three-step one-pot metal-free domino procedure yielding a set of boscalid
derivatives, parent compound being a highly important agrochemical agent. The first step of the process consists of the
Diels–Alder reaction between a substituted
2H-
pyran-2-one and styrene
derivatives, followed by the elimination of CO
2 and
aromatization (oxidation). The last step was found to be efficiently promoted by the application of
chloranil as the oxidant. Alternatively,
activated carbon Darco KB could also act as the
dehydrogenation catalyst necessitating a larger excess of the
styrene to act as the hydrogen acceptor.