Preparation of halo enol phostones by reaction of acetylenic phosphonate monoesters with (bis-collidine)halo hexafluorophosphate

Transition-Metal-Free Electrochemical Selenylative Cyclization of Alkynyl Phosphonates

Unprecedented regioselective electrochemical tandem selenation/cyclization of alkynyl phosphonates with diselenide is described here. These obtained selenoether products can be chemo-selectively converted into halogen-functionalized cyclic enol phosphonates under our electrochemical conditions. These protocols provide straightforward access to valuable cyclic enol phosphonate or phosphaisocoumarins under the electrochemical and transition-metal-free conditions. The robustness of these transformations was illustrated by their compatibility with various complex natural products and bioactive molecules. The selenoether and halogen functional groups allow the further diversification of the phosphorus heterocycles thus obtained.

Synthesis of medium and large phostams, phostones, and phostines

Phostams, phostones, and phostines are a series of 1,2-azaphosphaheterocycle and 1,2-oxaphosphaheterocycle 2-oxide derivatives. They are phosphorus analogues of lactams and lactones and important biologically active compounds. The strategies for the synthesis of medium and large phostams, phostones, and phostines are summarized. They include cyclizations and annulations. Cyclizations achieve ring construction through the formations of C-C, C-O, P-C, and P-O bonds in the rings, while annulations build the rings via [5 + 2], [6 + 1], and [7 + 1] fashions with the stepwise formation of two ring bonds. This review includes the recent syntheses of seven to fourteen-membered phostam, phostone, and phostine derivatives.

Ti-Catalyzed Cross-Cyclomagnesiation of 1,2-Dienes in the Total Z,Z,Z-Stereoselective Synthesis of Natural Acetogenin-Chatenaytrienin-1

The first total synthesis of natural acetogenin, chatenaytrienin-1, was performed in 10 steps and in 41% overall yield using cross-cyclomagnesiation of (6Z)-heptadeca-1,2,6-triene and trideca-11,12-dien-1-ol tetrahydropyran acetal with EtMgBr in the presence of Mg metal and the Cp₂TiCl₂ catalyst (10 mol %) as the key step of the synthesis.

Transition metal-free access to 3,4-dihydro-1,2-oxaphosphinine-2-oxides from phosphonochloridates and chalcones through tandem Michael addition and nucleophilic substitution

3,4-Dihydro-1,2-oxaphosphinine 2-oxides are synthesized through tandem intermolecular nucleophilic addition and cyclization of phosphonochloridates and enones in the presence of base.

Synthesis and antidepressant-like activity of selenophenes obtained via iron(III)-PhSeSePh-mediated cyclization of Z-selenoenynes

We present here the synthesis and antidepressant-like action of a series of 2,5-disubstituted-3-(organoseleno)-selenophenes prepared by a novel synthetic route, the FeCl(3)-diorganyl dichalcogenide-mediated intramolecular cyclization of (Z)-chalcogenoenynes. The cyclized products were obtained in good yields. The results showed that 2c, 2d, 2e and 2o, evaluated in the mouse forced-swimming test, elicited an antidepressant-like activity. The studies clearly show that the phenyl group at the 2-position and an organoselenium group at the 3-position of the selenophene ring are essential for the antidepressant-like activity of selenophenes. A close inspection of the results also revealed that the fluorophenyl portion in the organoselenium group is fundamental for the antidepressant-like action of this class of organochalcogens.