Synthesis of enantiomerically pure model compounds of the glucose-6-phosphate-T1-translocase inhibitors kodaistatins A–D. Inferences with regard to the stereostructure of the natural products

PS-BEMP as a basic catalyst for the phospha-Michael addition to electron-poor alkenes

PS-BEMP was used as a heterogeneous catalyst for the phospha-Michael addition of phosphorus nucleophiles to a variety of electron-poor alkenes. The addition reactions were generally performed with equimolar amounts of reagents under solvent free conditions. The protocol proved to be very efficient for the addition to aromatic, non-aromatic and cyclic ketones, giving good yields (78-85%) in all cases. The protocol was also extended with good results to α,β-unsaturated esters and nitriles. This demonstrates that PS-BEMP is a good catalyst for the phospha-Michael addition to electron-poor alkenes.

Stereogenic phosphorus-induced diastereoselective formation of chiral carbon during nucleophilic addition of chiral H-P species to aldehydes or ketones

P,C-stereogenic α-hydroxyl phosphinates or phosphine oxides were prepared from the additions of (RP)-phosphinate to ketones or (RP)-phosphine oxide to aldehydes, respectively, catalyzed by bases at room temperature in up to >99:1 diasteromeric ratio (d.r.P/d.r.C) and 99 % yields. The diastereoselectivity was induced by reversible equilibrium and different stabilities between two diastereomers of adduct, which was caused by the spatial interaction between menthoxyl or menthyl to alkyl groups of aldehydes or ketones.