Title of article :
Amino-zinc-ene-enolate cyclisation: a short access to (2S,3R)- and (2S,3S)-3-benzylprolines (3-benzylpyrrolidine-2-carboxylic acids)
Author/Authors :
Jean Quancard، نويسنده , , Jean and Magellan، نويسنده , , Hervé and Lavielle، نويسنده , , Solange and Chassaing، نويسنده , , Gérard and Karoyan، نويسنده , , Philippe، نويسنده ,
Abstract :
The synthesis of 3-benzylprolines can be easily achieved in a diastereoselective and enantioselective way via amino-zinc-ene-enolate cyclisation. Transmetalation of the cyclic zinc intermediate with Pd2(dba)3/P(o-Tolyl)3 allowed functionalisation with an aromatic ring. One-pot hydrogenolysis and Boc-protection led to the cis-isomer readily usable for peptide synthesis. The trans-isomer was obtained by epimerisation of the α-centre in a sealed tube at 200 °C.
