Li Q.
Zhao K.
Peuronen A.
Rissanen K.
Enders D.
*
Tang Y.
* Tsinghua University, Beijing and Sichuan University, Chengdu, P. R. of China; RWTH
Aachen University, Germany; University of Jyväskylä, Finland
Enantioselective Total Syntheses of (+)-Hippolachnin A, (+)-Gracilioether A, (–)-Gracilioether
E, and (–)-Gracilioether F.
J. Am. Chem. Soc. 2018;
140: 1937-1944
Key words
Plakortin polyketides - (+)-hippolachnin A - gracilioethers - organocatalysis - [2+2] photocycloaddition
- HAT-triggered oxygenation
Significance
(+)-Hippolachnin A and the gracilioethers commonly feature a strained, bowl-shaped
tricyclic core. Based on a [2+2]-photocycloaddition strategy, the authors report divergent
syntheses of four different Plakortin natural products.
Comment
An organocatalytic, asymmetric 1,4-addition afforded γ-butenolide D, which served as a common intermediate. Chain elongation gave ester G, which after desaturation and [2+2] photocycloaddition, yielded (+)-hippolachnin
A.
