A delicate balance of energetics. Subtleties associated with alpha-ketol-based bridge migration to afford 9-keto-10beta-p-methoxybenzyloxytaxanes |
| |
Authors: | Paquette Leo A Lo Ho Yin Hofferberth John E Gallucci Judith C |
| |
Affiliation: | Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA. paquette.1@osu.edu |
| |
Abstract: | The feasibility of the title reaction has been pursued for the purpose of advancing a concise total synthesis of Taxol. Of the two closely related series examined, the first featured an exo-methylene group at C4. The second consisted of an alpha-epoxide at that site. Strikingly, the olefinic construct proved inert to attempted alpha-ketol rearrangement. In contrast, the oxiranyl derivative isomerized smoothly. The reaction sequence associated with arrival at taxane 18 is short (15 steps from a D-camphor derivative) and notably efficient. The thermodynamic issues that are raised by this investigation have been clarified by an assessment of molecular mechanics-derived (MM3) steric energy calculations. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|