125113-57-7Relevant articles and documents
Enantioselective synthesis of (R)-1-azaspiro-[4.4]nonane-2,6-dione ethylene ketal, key chiral intermediate in the elaboration of (-)-cephalotaxine
Pizzonero, Mathieu,Dumas, Francoise,d'Angelo, Jean
, p. 31 - 37 (2005)
An enantioselective synthesis of (R)-1-azaspiro[4.4]nonane-2,6-dione ethylene ketal (4), chiral relay in the elaboration of (-)-cephalotaxine (1b), starting from (R)-1-(2-methoxycarbonylethyl)-2-oxo-cyclopentanecarboxylic acid methyl ester ((R)-10) (8 chemical operations, 26% overall yield, ee ≥ 95%) is described. The Curtius rearrangement of acyl azide (12) was used as the key strategic element to install with a perfect stereochemical fidelity and a high efficiency an α-nitrogen substituent at the quaternary carbon center in 10.
