The preparation of 9-substituted Δ5-octenolides: Synthesis of 8-deoxy-pseudo-ascidiatrienolide C
作者:Grant A. McNaughton-Smith、Richard J.K. Taylor
DOI:10.1016/0040-4020(95)01028-9
日期:1996.2
Two routes have been explored for the preparation of the title 9 membered lactones. Lactonisation of a hydroxy acid bearing an embryonic unsaturated side chain followed by palladiumcatalysed chain extension was shown to be problematic. The preferred procedure, which involved prior formation of the complete carbon skeleton followed by lactonisation using Mukaiyama conditions, was employed to prepare
New Silicon-Mediated, Sequential Ring Expansions of <i>n</i>-Sized 2-Cycloalkenones into Hydroxyolefinic <i>n</i> + <i>m</i> + <i>p</i> Medium-Sized Lactones: Short Synthesis of (−)-Phoracantholide-J
作者:Gary H. Posner、Mark A. Hatcher、William A. Maio
DOI:10.1021/ol051854x
日期:2005.9.1
In only four steps from 2-cyclopentenone and 2-cyclohexenone, sequential three- or four-atom and then one- to three-atom ring enlargements produce nine- to 12-membered hydroxyolefinic lactones on a gram scale. 2-Cyclopentenone undergoes this serial 5 + 3 + 2 process to form 10-membered ring natural (-)-phoracantholide-J in six linear steps and 26% overall yield.