SYNTHESIS OF 3-ALKYLPYRROLIDINES BY ANIONIC CYCLIZATION

alpha-Aminocarbanions, generated by transmetallation of aminomethylsta nnanes, cyclize onto an unactivated alkene to give 3-alkylpyrrolidines . The intermediate organolithium either reincorporates trimethyltin or , from the tributylstannanes, can be trapped with a variety of electro philes. From the trimethylstannane, the cyclization can be promoted ca talytically using 0.2 equivalents of methyllithium. The trimethyltin g roup in the product can be cleaved using eerie ammonium nitrate. Trapp ing the 3-lithiomethylpyrrolidine with ethylchloroformate, followed by hydrolysis provides a four step synthesis of the GABA uptake inhibito r 3-pyrrolidineacetic acid. Copyright (C) 1996 Elsevier Science Ltd