Design of sulfides with a locked conformation as promoters of catalytic and asymmetric sulfonium ylide epoxidation

[reaction: see text] A new generation of 2,5-dimethylthiolanes with a locked conformation was developed to promote the asymmetric addition of chiral sulfonium ylides to aldehydes. The novel chiral sulfur derivative 4 succeeded the synthesis of trans-stilbene oxide derivatives with enantiomeric ratios ranging from 95:5 to 98:2. This user-friendly organocatalytic process proved to be efficient with 20-10% of sulfide 4 in 1 or 2 days of reaction. An insight into the ylide intermediate conformation is given on the basis of a computational ab initio study.

Synthesis of 4-Arylideneisochroman-1,3-Dione under Microwave Irradiation

Homophthalic acid (1) and arylcarboxyaldehydes were condensed to form 4-arylideneisochroman-1,3-dione (3) in acetic anhydride in the presence of ammonium acetate under focused microwave irradiation. The stereochemistry of the products was determined by NMR and by X-ray diffraction of one isomer.

A one step process for grafting organic pendants on alumina via the reaction of alumina and phosphonate under microwave irradiation

Phosphonate esters react with gamma-alumina under microwave (MW) irradiation; this reaction is a simple preparative method to graft organic pendant groups onto the surface of alumina; the efficiency of the grafting was readily checked by solid-state NMR techniques (31P and 27Al).