Synthesis of Enantiomeric Pure E-Nor-15-azayohimbines
作者:Nativitat Valls、Josep Bonjoch、Carlos Del Alamo、Joan Bosch
DOI:10.1002/hlca.19920750110
日期:1992.2.5
A stereodivergent synthesis of enantiomericallypureE-nor-15-azayohimbines via condensation of tryptamine with derivatives of pyroglutamate 4 is reported. When the Pictet-Spengler reaction was induced in refluxing aqueous AcOH a nearly equimolar ratio of lactams 7 and 8 was obtained, whereas under kinetic control (TFA, room temperature) the trans-derivative 8 was the major product. In contrast, cyclization