Asymmetric total syntheses of (–)-ar-turmerone, (–)-dihydro-ar-turmerone, (–)-ar-dehydrocurcumene, and (–)-ar-himachalene via a key allylic oxidative rearrangement

[Display omitted] •A Nature inspired oxidative strategy to aromatic bisabolanes has been envisioned.•An oxidative [3,3]-sigmatropic rearrangement offers a direct entry to oxidized bisabolanes.•Rh(I)-(S)-BINAP catalyzed p-tolylboronic acid addition onto crotonates sets the required stereocenter.•Total Syntheses of (-)-ar-Turmerone, (-)-Dihydro-ar-turmerone, (-)-ar-Dehydrocurcumene, and (-)-ar-Himachalene has been shown. A Nature inspired strategy to oxidized aromatic bisabolanes has been envision from naturally occurring 2-methyl-6-(4′-methylphenyl)-3-hepten-2-ol (2a). The key methodology utilized in this synthesis is the allylic oxidative rearrangement following a [3,3]-sigmatropic rearrangement (Dauben oxidation) of tertiary allylic alcohol of natural product 2a. The enantioselectivity of 2a has been introduced via a Rh(I)-(S)-BINAP catalyzed p-tolylboronic acid addition onto E-ethylcrotonate. Thus, the total syntheses of (–)-ar-turmerone (1a), (-)-dihydro-ar-turmerone (1b) and (-)-ar-himachalene (3) has been achieved only in 6–7 steps.