Total Synthesis of Onitin

Abstract

The total synthesis of the phenolic sesquiterpene onitin using dimethylated indanone as the key intermediate is reported. Key to the success of this synthesis route is the Suzuki-Miyaura cross-coupling reaction of aryl bromide to introduce the vinyl side chain followed by formyl selective Wacker oxidation to generate the aldehyde. The target aldehyde was also obtained in high overall yield via an acid-catalyzed pinacol-pinacolone-type rearrangement of the epoxide. The epoxide was generated from oxidation of a styrene derivative by oxone. Demethylation of the aldehyde followed by chemoselective reduction furnished onitin.

Head and Tail Oxidized Terpenoid Esters from Androconia of Heliconius erato Butterflies

“…Again, the different compounds proved to be inseparable. Finally, the aldehyde group was reduced with sodium trisacetoxyborohydride, leaving the ketone intact . Alcohol 6 was obtained in a 20% yield, with no traces of the possible diol.…”

“…The reaction mixture was stirred at 0 °C for 30 min and then at rt for an additional 2.5 h. Saturated NH 4 Cl solution was added, and the aqueous layer was extracted with CH 2 Cl 2 (3 × 10 mL). The combined organic phases were dried over MgSO 4 , and the solvent was removed under reduced pressure . The product was purified through column chromatography using pentane and diethyl ether (7:3) as solvents.…”

DFT studies on rhodium(iii)-catalyzed synthesis of indanones from N-methoxybenzamides via C–H activation reaction

“…The indane structure is widely found in many natural products, pesticides and medicines. [1][2][3] It can be used to prepare various biological active substances, agricultural chemicals and drugs. 4 The indanone derivatives can be used in the synthesis of various products, such as anticancer drugs, anti-inflammatory drugs and pharmaceuticals for treating Alzheimer's disease.…”

Umpolung Chemo- and Regioselective Cascade Addition of Diethylzinc to α-Diketones Followed by Intramolecular Michael Reaction: Stereoselective Synthesis of Highly Substituted 1- Indanones

“…Notably, 1-indanone is obtained in numerous pharmaceutically important natural products (Figure ). For example, donepezil is a cardiovascular drug and is also useful for Alzheimer’s disease treatment; pterosin B, pterosin Z, and onitin are antiviral and antibacterial drugs; (+)-indacrinone is an antihypertensive drug; celludinone A1 and celludinone A2 act as sterol O -acyltransferases; pucifloral has antibiotic, anti-HIV, and other biological activities; benzylidene-indanone is an anticancer drug; and so on. Indanones also serve as key precursors in the synthesis of many architecturally complex and diverse pharmaceuticals .…”