Design of potential new HIV protease inhibitors: enantioconvergent synthesis of new pyrrolidin-3-ol, and pyrrolidin-3-one peptide conjugates

Novel potential HIV protease inhibitors are obtained by an enantioconvergent synthesis of mimicking Phe-Pro dipeptides, achieved through the coupling between Boc(L)Phe or Boc(L)Tyr and both enantiomers of syn-2-benzylpyrrolidin-3-ol and their corresponding pyrrolidin-3-one analogs. The stereochemistry and enantiopurity of intermediate 3-hydroxypyrrolidines 5a and 5b are determined through 1H NMR analysis, and through the synthesis and 19F NMR assignments of the corresponding Mosher’s esters 13a and 13b. The enantiopure compounds 5a and 5b are obtained with 100% diastereoselectivity using specific experimental reductive conditions upon Meldrum’s acid derivatives of activated aromatic amino acids.