Enantio- and Stereoselective Construction of Atisane Scaffold via Organocatalytic Intramolecular Michael Reaction and Diels–Alder Reaction

Highly Stereoselective Diels-Alder-Based Strategy for the Synthesis of 3-epi-Formicin A and 1-epi-Formicin B

The first enantioselective approach based on a highly stereoselective Diels-Alder reaction for the synthesis of 3-epi-formicin A and 1-epi-formicin B with rare N-acetylcysteamine-containing indenone thioesters is reported. The strategy utilizes a key Diels-Alder reaction to form the core hydrindane system with three contiguous stereocenters in very high levels of diastereo- and regioselectivity and one-pot oxidation/isomerization/dehydrogenation. The scope of this method was tested with different substrates to give cycloadducts in a highly diastereoselective manner.

Pd-Catalyzed Stereoselective Construction of Benzo-Fused Decalines with a Quaternary Carbon

The Pd-catalyzed stereoselective construction of decalins with one-carbon units bearing heteroatoms at the ring junction is described. The Pd-catalyzed cyclization of silyl enol ether resulted in exclusive formation of the cis isomer (89%, >100/1 cis/trans). On the contrary, Pd-catalyzed carboiodination and carboborylation (with oxidative workup) provided products in 56% yield (1/>100 cis/trans) and 69% yield (1/11 cis/trans), respectively.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial sources from 2017.