Asymmetric Synthesis of Taiwaniaquinone H via a Late-Stage Oxidative Decarboxylation.

The asymmetric syntheses of naturally occurring biologically relevant -abietane diterpenoids, (-)-taiwaniaquinone G (), and H () have been reported via a chiral pool strategy starting from commercially available abietic acid. A ring contraction of the middle ring of the [6,6,6]-carbotricyclic abietane diterpenoid core was carried out under the Wolff rearrangement. Finally, the synthesis of (-)-taiwaniaquinone H () was completed via a one-pot CAN-mediated oxidative decarboxylation.

Total synthesis of bicyclomahanimbine by Cu(ii)-promoted photoredox process.

Since the isolation of carbazole alkaloids, the synthetic chemists have witnessed an upsurge in research of them due to their potential pharmacological properties. Our approach shows the total syntheses of five such biorelevant pyrano-[3,2]-carbazole alkaloids, emphasizing biomimetic and innovative synthetic methodologies such as cascade reactions and strategic bond formations through sustainable electrochemical and photochemical conditions.