Pipitzols and Isopipitzols, 1852 to 2026: A Review

A thorough review of pipitzols and isopipitzols, covering the period 1852–2026, is presented. Perezone, the precursor of these compounds, is considered to be the first secondary metabolite isolated on the American continent, a phyto-molecule widely studied with regard to its spectra, chemical transformations, and especially its isolation and pharmacological activities. Perezone has several isomers: isoperezone, a synthetic molecule; and α- and β-pipitzols, two natural isomers of cedrenoid type achieved by thermal exo [4+2] cycloadditions. Isoperezone can be isomerized to β-isopipitzol through an endo [4+2] cycloaddition, while α-isopipitzol can be obtained from perezone by a [1+3] dipole addition. For this review, we conducted a comprehensive literature search, employing the main Scopus, SciFinder®, and ResearchGate databases, which identified 148 references. We found that the most recent report on α- and β-pipitzols appeared in 2024, on α-isopipitzol appeared on 2 September 2026, and on the four isomers was published on 29 January 2026.