Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Green, solventless synthesis of phenanthrenes and asymmetric cascade reactions yield molecules of interest for the treament of malaria and HIV/AIDS. The control of crystalline form in the solid state have given complete regiochemical control in subsequent photochemical ring-closure of phenanthrenes. A subsequent asymmetric aldol condensation utilizing acetaldehyde as the donor led to an enantioselective synthesis of the phenanthrene-methanol shown, which is a more potent, non-toxic analog of the malaria drug halofantrine. Cl CHO Form 1 h Cl C l reductive amination OH OH C l N H Bu CH O Cl CHO C l C l N O2 Cl malaria drug C F3 Form 2 h C F3 C F3 CHO C F3 Stilbene A dif ferent crystalline f orms of the stilbene precursor yield dif f erent regiochemical isomers of the ring-closed phenanthrene N O2 C l C F3 NO2 Asymmetric Henry Reaction H RCHO CH 3CHO CHO R R NHCOR2 amino acid catalyst N H R R2 R NHR OH singl e-pot Cas cade rxn The asymmetric aldol or Mannich reaction of aldehydes or aldehyde imines with low-molecular weight aldehyde donors is a difficult reaction to control. We have achieved high enantioselectivities in these reactions using simple amino acids or derivatives thereof. The combination of an asymmetric Mannich reaction with an asymmetric Henry reaction in the same pot, using only a single catalyst, yielded good diastereoselection in the Henry reaction as well as excellent overall asymmetric induction. This yields the rapid construction of linear molecules with three asymmetric centers. These molecules are of interest for numerous applications, including the synthesis of protease inhibitors for the treatment of HIV/AIDS.