General stereocontrolled strategy for the heteroyohimbine alkaloids: the total synthesis of (-)-ajmalicine and (+)-19-epiajmalicine
摘要:
A general approach is described for the total synthesis of enantiomerically pure 3-alpha-heteroyohimbine alkaloids based on the utilization of D-glucose as a chiral template for ring E. 19-Epiajmalicine was thus prepared from alpha-D-glucose pentaacetate in 23 steps (2.5% overall yield), averaging 85% yield per step.