A Ring Synthesis
The A ring synthesis (Scheme 3) started with a Diels-Alder reaction of diene 3.1 with the commercially available dienophile 2-chloroacrylonitrile 3.2 to give cyclohexene 3.3 with complete regioselectivity. Hydrolysis of the cyanochloro group and simultaneous cleavage of the acetate group led to hydroxyketone 3.4. The hydroxyl group was protected as a tert-butyldimethylsilyl ether (3.5). In preparation for a Shapiro reaction, this ketone was converted to hydrazone 3.6.
| Scheme 3 |
|---|
Read more about this topic: Nicolaou Taxol Total Synthesis
Famous quotes containing the words ring and/or synthesis:
“The boxer’s ring is the enjoyment of the part of society whose animal nature alone has been developed.”
—Ralph Waldo Emerson (1803–1882)
“The spider-mind acquires a faculty of memory, and, with it, a singular skill of analysis and synthesis, taking apart and putting together in different relations the meshes of its trap. Man had in the beginning no power of analysis or synthesis approaching that of the spider, or even of the honey-bee; but he had acute sensibility to the higher forces.”
—Henry Brooks Adams (1838–1918)