Synthesis of d- and l-2,3-trans-3,4-cis-4,5-trans-3,4-Dihydroxy-5-hydroxymethylproline and Tripeptides Containing Them
journal contributionposted on 25.06.2004, 00:00 by Antonio J. Moreno-Vargas, Inmaculada Robina, Elena Petricci, Pierre Vogel
Enantiomerically pure (−)-(1R,4R,5R,6S)- and (+)-(1S,4S,5S,6R)-7-(tert-butoxycarbonyl)-5,6-exo-isopropylidenedioxy-7-azabicyclo[2.2.1]hept-2-one ((−)-3 and (+)-3) have been obtained from the Diels−Alder adduct of N-(tert-butoxycarbonyl)pyrrole and 2-bromo-1-(p-toluenesulfonyl)acetylene, including the Alexakis optical resolution of ketone (±)-3 via formation of cyclic aminals with (1R,2R)-diphenylethylenediamine. Compounds (−)-3 and (+)-3 were converted into d- and l-2,3-trans-3,4-cis-4,5-trans-N-(tert-butoxycarbonyl)-5-hydroxymethyl-3,4-isopropylidenedioxyprolines (−)-4 and (+)-4, respectively. Applying the Boc and Fmoc strategies of peptide synthesis, these compounds were used to construct two tripeptides containing the d- or l-2,3-trans-3,4-cis-4,5-trans-3,4-dihydroxy-5-hydroxymethylproline.