The Synthesis of a Cubane-Substituted Dipeptide

Amino acids and peptides bearing cyclic hydrocarbon side-chains are of interest in the development of a wide range of bioactive molecules. The preparation of an amino acid and a dipeptide derivative bearing an unfunctionalised cubane substituent is described. Attempts to prepare a cubylalanine derivative via the corresponding dehydroalanine were unsuccessful due to the high sensitivity of this vinyl cubane compound. Conversely, the addition of cubyllithium to a (R-S)-glyoxylate sulfinimine led to an effective synthesis of a cubylglycine derivative and a cubane-substituted dipeptide in diastereomerically pure form.