Simple Synthesis of<i>trans</i>-<i>α</i>,<i>β</i>-Dibenzyl-<i>γ</i>-butyrolactone Lignans by Diastereoselective Reduction of<i>α</i>-Benzylidene-<i>β</i>-benzyl-<i>γ</i>-butyrolactones Using NaBH<sub>4</sub>–NiCl<sub>2</sub>
作者:Yasunori Moritani、Chiaki Fukushima、Toshikazu Miyagishima、Hiroshi Ohmizu、Tameo Iwasaki
DOI:10.1246/bcsj.69.2281
日期:1996.8
ne lignans were synthesized by stereoselective reduction of α-benzylidene-β-benzyl-γ-butyrolactones using NaBH4–NiCl2. The reduction is found to proceed via conjugate addition of a hydride to an α-benzylidene-β-benzyl-γ-butyrolactone and the stereoselective protonation of the resulting metal enolate. The stereoselectivity would be brought about by the conformational rigidity of the phenyl moiety of
反式-α,β-二苄基-γ-丁内酯木脂素是通过使用NaBH4-NiCl2立体选择性还原α-苄叉-β-苄基-γ-丁内酯合成的。发现还原是通过氢化物与 α-亚苄基-β-苄基-γ-丁内酯的共轭加成和所得金属烯醇化物的立体选择性质子化来进行的。立体选择性是由 1,3-烯丙基应变诱导的 α-苄基的苯基部分的构象刚性带来的。