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Sixteen geosterane derivatives were synthesized in up to 57 % overall yields in four steps harnessing the olefin cross‐metathesis (OCM) and Metal hydride H atom transfer (MHAT) or homogeneous hydrogenation reactions as key steps. Drawing on this strategy, the diastereomeric ratio (d. r.) reached up to 24 : 1 for the thermodynamic isomer and 7 : 1 for the other isomer in the hydrogenation step. In a geological sample from northeast Brazil, we confirmed the putative structures previously assumed as methyl 2‐(3α‐5αH‐cholestan) acetate, methyl 2‐(3β‐5αH‐cholestan)acetate, and methyl 6‐(3β‐5αH‐cholestan)hexanoate, as well three new molecular fossils of approximately 120 million years old. We also proved the migration marking ability of those carboxylic acids derived from forerunner geosteranes during an oil migration event, which suggests their aptitudes as molecular odometers. Our approach demonstrated swiftness and effectiveness in preparing a molecular library of geological biomarkers would also be appropriate to generate stereochemical diversity in molecular libraries for medicinal chemistry and natural product anticipation. [ABSTRACT FROM AUTHOR]

The article presents a study on dyke swarms in Sao Francisco cratons in Brazil. The petrogenetc and tectonic significance of the dyke swarms are studied.The emplacement ages and coupled geo chemical and isotopic data in the light of long lived poly cyclic evolution of the basement rocks and the underneath subcontinental mantle through time are reassessed.