Total synthesis of (±)-cafestol: A late-stage construction of the furan ring inspired by a biosynthesis strategy
An efficient bioinspired approach to the total synthesis of (±)-cafestol features a late-stage installation of the furan ring with a mild Au-catalyzed cycloisomerization. The Et2AlCl-promoted aldehyde-ene cyclization and subsequent Friedel-Crafts reaction deliver a requisite tricyclic system in gram scale with high stereo- and regioselectivity. Moreover, a highly stereoselective SmI2-mediated aldehyde-alkene radical cyclization furnishes the key bicyclo[3.2.1]octane skeleton to offer an advanced intermediate for the synthesis of other oxygenated ent-kaurene diterpenoids.
Zhu, Lili,Luo, Jisheng,Hong, Ran
p. 2162 - 2165
(2014/05/06)
Preparation of cafestol
A process for the preparation of cafestol from kahweol wherein the kahweol is hydrogenated in the presence of a partially deactivated palladium catalyst on a calcium carbonate or active carbon support conditioned by lead. A process for preparing a mixture of cafestol and kahweol by treating coffee oil with anhydrous methanol in the presence of a basic catalyst is also disclosed.
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(2008/06/13)
Stereospecific Total Synthesis of (+/-)-Cafestol
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Corey, E. J.,Wess, Guenther,Xiang, Yi Bin,Singh, Ashok K.