210841-59-1Relevant articles and documents
A new approach to 5-substituted prolines and 2-pyrrolecarboxylates
Knight, David W.,Redfern, Adele L.,Gilmore, Jeremy
, p. 731 - 732 (1998)
Iodocyclisations of the allylic glycinates 7 lead either to the trans- or cis-2,5-disubstituted proline derivatives 8 or 9, depending on the reaction conditions; subsequent treatment of these with DBU in DMF gives the 2-pyrrolecarboxylates 10 and 13 in excellent yields by a double elimination of hydrogen iodide and toluenesulfinic acid.
Transition metal-catalyzed synthesis of pyrroles from dienyl azides
Dong, Huijun,Shen, Meihua,Redford, Joanne E.,Stokes, Benjamin J.,Pumphrey, Ashley L.,Driver, Tom G.
, p. 5191 - 5194 (2008/09/17)
(Chemical Equation Presented) A range of 2,5-disubstituted and 2,4,5-trisubstituted pyrroles can be synthesized from dienyl azides at room temperature using catalytic amounts of Znl2 or Rh2(O 2CC3F7)4.
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 with respect to 5-exo cyclisations
Knight,Redfern,Gilmore
, p. 2874 - 2883 (2007/10/03)
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 compete successfully with the sulfonamide via a 5-exo cyclisation mode. However, when such a substrate contains a furan ring attached to the alkene function (21), then cyclisation does occur at the sulfonamide, presumably by participation of the furan oxygen, to give an iodopyrrolidine-2-methanol 13a. Finally, base-induced elimination of both hydrogen iodide and toluene-p-sulfinic acid from the initial iodopyrrolidines 11 and 12 leads to 5-substituted pyrrole-2-carboxylates 26. Overall, this sequence is complementary to the Kenner pyrrole synthesis.