Conversion of Conjugated Enones into Enantiomerically Pure -Hydroxy Ketones or 1,3-Diols - Samarium(II) Bromide Reductions of Protected ,-Dihydroxy Ketones
作者:Andreas Zörb、Reinhard Brückner
DOI:10.1002/ejoc.201000279
日期:2010.9
Asymmetric dihydroxylations of α,β-unsaturated ketones in the presence of Sharpless' AD mix-β™ delivered α,β-dihydroxy ketones or, if phenylboronic acid was present, the corresponding phenylboronates. The C α ―O bonds of these species were removed at ―78 °C ― in the former case after acetonide formation, in the latter case directly ― in an unprecedented manner, namely by treatment with a suspension
在 Sharpless 的 AD mix-β™ 存在下,α,β-不饱和酮的不对称二羟基化产生 α,β-二羟基酮,如果存在苯基硼酸,则生成相应的苯基硼酸酯。这些物种的 C α -O 键在 -78 °C 下被去除 - 在前一种情况下是在丙酮化物形成后,在后一种情况下直接 - 以前所未有的方式,即通过用 Sm II 溴化物在 THF/MeOH 中的悬浮液处理. 如果需要,可以还原所得的单羟基酮以得到顺式或反式构型的 1,3-二醇。在 0 °C 下用 Sm II 溴化物一锅还原 α,β-二羟基酮双丙酮化物,产生相同的二醇。当同样处理α,β-二羟基酮苯基硼酸酯时,得到1,3-二醇的苯基硼酸酯。