A Friedel-Crafts cyclization approach toward cephalotaxine
摘要:
The 1-azaspiro[4.4]nonane portion 11 of cephalotaxine was prepared via an intramolecular S(N)2' substitution reaction followed by ozonolysis; condensation of 11 with the aromatic portion 13 gave compound 15; a Friedel-Crafts cyclization of 15 in polyphosphoric acid smoothly afforded the cephalotaxine skeleton 16. A single-crystal X-ray analysis of the HCl salt of 16 confirmed the structure of 16.
A Friedel-Crafts cyclization approach toward cephalotaxine
摘要:
The 1-azaspiro[4.4]nonane portion 11 of cephalotaxine was prepared via an intramolecular S(N)2' substitution reaction followed by ozonolysis; condensation of 11 with the aromatic portion 13 gave compound 15; a Friedel-Crafts cyclization of 15 in polyphosphoric acid smoothly afforded the cephalotaxine skeleton 16. A single-crystal X-ray analysis of the HCl salt of 16 confirmed the structure of 16.