Asymmetric Total Syntheses of 8, 9‐Seco‐ent‐kaurane Diterpenoids Enabled by an Electrochemical ODI‐[5+2] Cascade. (4th June 2021) - Wang, Bingnan
Abstract: An electrochemical ODI‐[5+2] cascade reaction was developed which enables the rapid assembly of diversely functionalized bicyclo[3.2.1]octadienones from sensitive ethynylphenols. By combining a directed retro‐aldol/aldol process, a [2, 3]‐sigmatropic rearrangement, and an Al(O‐iPr)3 ‐promoted reductive 1, 3‐transposition, the asymmetric total syntheses of five 8, 9‐seco‐ent‐kauranoids—(−)‐shikoccin, (−)‐O‐methylshikoccin, (−)‐epoxyshikoccin, (+)‐O‐methylepoxyshikoccin, and (+)‐rabdo‐hakusin—have been achieved in a concise and efficient manner. Abstract : An efficient ODI‐[5+2] cascade reaction of sensitive ethynylphenols was achieved under mild electrochemical conditions, which led to the rapid construction of a series of bicyclo[3.2.1]octadienone skeletons. By incorporation of a directed retro‐aldol/aldol process, a [2, 3]‐sigmatropic rearrangement and an Al(O‐ i Pr)3 ‐promoted reductive 1, 3‐transposition, the asymmetric total syntheses of five 8, 9‐seco‐ ent ‐kauranoids have been accomplished.