Synthesis of Luffarin L and 16-<i>epi</i>-Luffarin L Using a Temporary Silicon-Tethered Ring-Closing Metathesis Reaction

The first synthesis of luffarin L (<b>1</b>) and 16-<i>epi</i>-luffarin L (<b>2</b>) by a silicon-tethered ring closing metathesis as a key step has been achieved. The stereochemistry and absolute configuration of the natural sesterterpenolide luffarin L (<b>1</b>) and a new route for the stereoselective synthesis of sesterterpenolides with a luffarane skeleton have been established

Biomimetic Synthesis of Two Salmahyrtisanes: Salmahyrtisol A and Hippospongide A

Sesterterpenes with a salmahyrtisane skeleton have been synthesized for the first time. (−)-Sclareol has been selected as a precursor for the synthesis of two novel natural products: salmahyrtisol A (<b>1</b>) and hippospongide A (<b>2</b>). Our results represent a biomimetic approach to obtaining salmahyrtisanes from hyrtiosanes. Salmahyrtisol A has shown an activity comparable to that of the standard anticancer drugs in the cell lines A549, HBL-100, HeLa, and SW1573

Diastereoselective synthesis of chiral 1,3-cyclohexadienals

<div><p>A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of a Jørgensen-Hayashi organocatalyst provides easy and stereocontrolled access to the cyclohexadienal backbone. This method allows for the synthesis of potential photoprotective chiral 1,3-cyclohexadienals and extra extended conjugation compounds in a simple manner.</p></div

Experimental optimization of synthesis of chiral cyclohexadienals (4a, 4b) from citral (1) and α,β-unsaturated aldehyde 2.

<p>Experimental optimization of synthesis of chiral cyclohexadienals (4a, 4b) from citral (1) and α,β-unsaturated aldehyde 2.</p

Synthesis of different chiral cyclohexadienals aromatic and non-aromatic compounds.

<p>Synthesis of different chiral cyclohexadienals aromatic and non-aromatic compounds.</p

General reaction to obtain chiral cyclohexadienals.

<p>General reaction to obtain chiral cyclohexadienals.</p

Synthesis of bicycle 12 from cyclohexadienal 4a.

<p>Reagents: a) NaH₂PO₄^.H₂O (2.2 equiv.), NaClO₂ (5%, 2.2 equiv.), 2-methyl-2-butene, <i>t</i>BuOH, r.t., 2h, 99%; b) <i>p</i>-TsOH, MeOH, r.t., 30%.</p

Proposal for the synthesis of new cyclohexadienal building blocks using different catalysts.

<p>Proposal for the synthesis of new cyclohexadienal building blocks using different catalysts.</p

UV-Vis absorbance spectra at different λ of 4a, 20b, 21b, 22b, 23a, 23b.

<p>Amplification of the 200–450 nm region and the delimited UVA and UVB regions (ISO-21348).</p

The area of regions UVA (315–400 nm) and UVB (280–315 nm) and molar extinction coefficient of some cyclohexadienals (4a, 20b, 21b, 22b, 23a, 23b) dissolved in <i>i</i>PrOH.

<p>The area of regions UVA (315–400 nm) and UVB (280–315 nm) and molar extinction coefficient of some cyclohexadienals (4a, 20b, 21b, 22b, 23a, 23b) dissolved in <i>i</i>PrOH.</p