Synthetic Studies towards Delta6-Protoilludene. A Formal Synthesis.
作者:Trond Vidar Hansen、Stephen M'dachi、Lars Skattebøl、Yngve Stenstrøm
DOI:10.3891/acta.chem.scand.52-1373
日期:——
A synthetic strategy towards Delta(6)-protoilludene included an intramolecular allene-ene cycloaddition reaction as a key step; however, the thermal reaction furnished a stereoisomeric mixture of 9-methyl-1,4,4,8-tetramethyltricyclo[6.2.0.0(2,6)]decane, which has a ring assembly isomeric with that of the target molecule. Another approach to Delta(6)-protoilludene required cis-4,4-dimethyl-2-isopropenylcyclopentylacetic acid, which was obtained from the mixture of stereoisomers by column chromatographic separation of the corresponding iodolactones. The cis-acid was further converted into cis-ethyl 4-(2-isopropenyl-4,4-dimethylcyclopentyl)-3-methyl-2-butenoate which has previously been transformed by others into Delta(6)-protoilludene. Hence, our approach constitutes formally a new synthesis of Delta(6)-protoilludene.