Total synthesis of the proposed structure of Anti-TMV active tabasesquiterpene A

Article abstract of DOI:10.1016/j.tet.2021.132282

The proposed structure of Tabasesquiterpene A, an illudalane type of sesquiterpene has been synthesized in twelve steps from 2-methoxy-4-methylbenzaldehyde in 40% overall yield. Triflic acid mediated intramolecular Freidel-Crafts acylation allows to develop the critical indanone moiety, a key intermediate of this synthesis. A careful ortho-selective formylation and subsequent Knoevenagel condensation to incorporate three carbon side chain, followed by reduction, formation of tricyclic lactone and DIBAL-H supported reduction of lactone to target were other key transformation involved. The NMR spectroscopic data of the synthetic sample differ from those of natural tabasesquiterpene A.