Desymmetrisation of meso-methylcyclooctanones. Highly enantioselective synthesis of C8 syn-isoprenoid and syn,syn-deoxypropionate subunits from a bicyclo[3.3.1]nonane precursor
作者:Augusto Gambacorta、Daniela Tofani、Paolo Lupattelli、Andrea Tafi
DOI:10.1016/s0040-4039(02)00229-0
日期:2002.3
exo,exo-3,7-dimethylbicyclo[3.3.1]nonan-9-one, the key step involving the desymmetrisation of the intermediate meso-ketones cis-3,7-dimethyl- and cis,cis-3,5,7-trimethyl-cyclooctanone through the corresponding chiral enolates generated by the lithium amide of the (+)bis[(R)-(1-phenylethylamine)]. The very high enantioselectivity observed might be related to the conformational features of the eight-membered
3的甲基酯[R,7小号二甲基和3 - [R,5 - [R,7小号-三甲基- 8-羟基氨基酸已在良好的产率和ee值制备> 98%通过已知的化学的阐述外,外切- 3,7-二甲基二环[3.3.1]壬烷-9-酮,涉及中间体的去对称的关键步骤内消旋-酮的顺式-3,7-二甲基-和顺式,顺式-3,5,7-三甲基环辛通过(+)bis [(R)-(1-苯基乙胺)]。观察到的很高的对映选择性可能与八元环的构象特征有关。