Stereospecific synthesis of a 2β-H-indoloquinolizidinone: Key intermediate in indole alkaloids synthesis
作者:A. Pancrazi、J. Kervagoret、Q. Khuong-Huu
DOI:10.1016/s0040-4039(00)92154-3
日期:1991.1
The pyranose 4 yielded the 2-oxa-8-aza-bicyclo [3.3.1] nonane 14 by condensation with tryptamine 7; the intermediate acyliminium 18 led to the expected 2β-H-indoloquinolizidinone 15ab through a Pictet-Spengler cyclisation.
New approach in total synthesis of indole alkaloids was invented using carbohydrates. Stereocontrolled 15α-H and 15β-H derivatives such as 26a,b and 30a,b were obtained using the same sugar 24. A pure 3α-H, 15α-H compound 32a,b was also prepared an acyliminium intermediate in a Pictet-Spengler condensation with tryptamine.
obtained by condensation between pyranose 3 and tryptamine 4 ; in few steps, the indoloquinolizidine 13a was prepared with a perfect stereocontrol of the 2β-H configuration ; total synthesis of (−)-antirhine 2 was then achieved from 13a.