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
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
A New Approach to 5-Substituted Prolines and 2-Pyrrolecarboxylates
作者:David W. Knight、Adele L. Redfern、Jeremy Gilmore
DOI:10.1055/s-1998-1768
日期:1998.7
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.