Preparation of (1R,4R)-1-methyl-2-(p-toluenesulfonyl)-5-phenyl-methyl-2,5-diazabicyclo [2.2.1] heptane, intermediate in a synthesis of new naphthyridones

An efficient chiral synthesis of the (1R,4R)-1-methyl-2-(p-toluenesulfonyl)-5-phenylmethyl-2,5-diazabicyclo [2.2.1]-heptane (2b) was performed using trans-4-hydroxy-L-proline as starting material. This bridged piperazine was used in the preparation of new naphthyridones (16) and (17)