Asymmetric synthesis of camptothecin alkaloids: A nine-step synthesis of (S)-camptothecin
β Scribed by Daniel L. Comins; Hao Hong; Gao Jianhua
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- French
- Weight
- 221 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0040-4039
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## Abstract A sixβstep asymmetric total synthesis of (20__S__)βcamptothecin (**1**) has been accomplished in 25% overall yield starting from the known pyridone **3**. The key steps in this synthesis are the chemoselective Niβcatalyzed hydrogenation of 3βcyanopyridone **6** to 3βformylpyridone **7**
A . F Wells. A<ru C'J I siuNogr. S c ~r A. 1986.42. 133. We are indebted to one of [7] G . M. Sheidrick. SHELX-76, Proxriiix /oi-C~.i..sro/ S i r i i m i t -c D ~, ~~~I -I I ~~I ~~I I ; ~J I ? . Condensation of phosphonate 4, Y = Z = H, with aldehyde 5 (vide infra) afforded enone 7, [ X I : ' = -56.