Amino acids as precursors to indolizidine alkaloids. DPPA-promoted decarbonylation of a bicyclic amino acid: An easy entry to hydroxylated indolizidines
作者:María J. Martín-López、Francisco Bermejo-González
DOI:10.1016/s0040-4039(00)78513-3
日期:1994.11
The synthesis of 8,8a-trans-8-hydroxy-indolizidine 12 from (D,L)-pipecolinic acid by two alternative routes is described. The stereospecific decarbonylation of the bicyclic carboxyamide 9 promoted by diphenylphosphorazidate (DPPA) is the key step of our strategy. The bicyclic enamide 10 is described as a valuable intermediate in the synthesis of hydroxylated indolizidines.
Decarbonylation of α-tertiary amino acids application to the synthesis of polyhydroxylated indolizidines from D,L-pipecolic acid
作者:María J. Martín-López、Rosa Rodriguez、Francisco Bermejo
DOI:10.1016/s0040-4020(98)00689-9
日期:1998.9
The decarbonylation of the bicyclic α-tertiary carboxamido acid 11 led to the enamide 12, easily transformed into the indolizidine alkaloid 8,8a-trans-8-hydroxy-indolizidine 14. Likewise, the same process applied to the α-substituted pipecolic acid derivative 5 led to the unsaturated ester 6 which was easily transformed either into δ-coniceine 9 or to 14. The thermal fragmentation of the acyl derivative