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.