(R)-(+)-[VCD(-)984]-4-Ethyl-4-methyloctane: A Cryptochiral Hydrocarbon with a Quaternary Chiral Center. (1) Synthesis of the Enantiopure Compound and Unambiguous Determination of Absolute Configuration
作者:Takuma Fujita、Kazuhiro Obata、Shunsuke Kuwahara、Atsufumi Nakahashi、Kenji Monde、John Decatur、Nobuyuki Harada
DOI:10.1002/ejoc.201000777
日期:2010.11
Enantiopure (R)-(+)-[VCD(-)984]-4-ethyl-4-methyloctane (1), a cryptochiral hydrocarbon with a quaternary chiral center, was synthesized by the use of 2-methoxy-2-(1-naphthyl)propionate (MaNP) and (-)-camphorsultam dichlorophthalic (CSDP) acid methods. The diastereomeric MαNP and CSDP acid esters prepared from racemic 2-butyl-2-methyl-1-tetralols, were effectively separated by HPLC on silica gel, and
Enantiopure (R)-(+)-[VCD(-)984]-4-ethyl-4-methyloctane (1),一种具有季手性中心的隐手性烃,是通过使用 2-甲氧基-2-( 1-萘基)丙酸酯 (MaNP) 和 (-)-樟脑磺胺二氯邻苯二甲酸 (CSDP) 酸方法。由外消旋 2-丁基-2-甲基-1-四醇制备的非对映异构 MαNP 和 CSDP 酸酯通过硅胶高效液相色谱法有效分离,其绝对构型通过 X 射线晶体分析和 1 H NMR 各向异性方法明确确定. 然后将回收的对映体纯 2-丁基-2-甲基-1-四氢萘酚 [(1S,2S)-(+)-cis-9] 转化为烃 (+)-1,明确确定其 R 绝对构型首次。碳氢化合物 1 的结构也通过 NMR HSQC-TOCSY 分析得到证实。