The synthesis of 5-substituted proline derivatives and of 5-substituted pyrrole-2-carboxylates by 5-endo cyclisations featuring a method for effectively favouring these …
DW Knight, AL Redfern, J Gilmore
文献索引:Knight; Redfern; Gilmore Journal of the Chemical Society. Perkin Transactions 1, 2001 , # 21 p. 2874 - 2883
Overall 5-endo cyclisations of the C-allylic glycine sulfonamides 5 lead to usually excellent yields of the 2, 5-cis-or 2, 5-trans-pyrrolidine-2-carboxylates 11 and 12 respectively, depending upon whether base is absent or present. While reductions to the corresponding pyrrolidine-2-methanols 13 proved efficient, subsequent eliminations of the elements of hydrogen iodide gave mixtures of products 14–16. Suitably positioned hydroxy groups ...