合成路线1

In a related procedure, the protected pyrrolidinone (II) was treated with 2,4,6-triisopropylbenzenesulfonyl azide and LDA to produce a 1:3.2 mixture of isomeric azides (XI) and (XII). After isolation of the major cis-isomer (XII), its catalytic hydrogenation over Pd/C yielded amine (XIII), which was subsequently protected as the N-Boc derivative (XIV). Reductive cleavage of the benzylidene group of (XIV) using Li in liquid ammonia provided the (hydroxymethyl)pyrrolidinone (XV). Reduction of the hydroxymethyl group to the methyl derivative (X) was effected via iodide (XVI) in a similar sequence as above.