Towards the synthesis of chiral isochromanquinones. The use of Corey–Bakshi–Shibata reductions
作者:Charles B de Koning、Robin G.F Giles、Ivan R Green、Nazeem M Jahed
DOI:10.1016/s0040-4039(02)00759-1
日期:2002.6
(1R,3R,4S)-3,4-Dihydro-4-hydroxy-6-methoxy-1,3-dimethylisochroman-5,8-dione has been synthesized in 65% ee from (1R,3R,4S)-5-benzyloxy-3,4-dihydro-4-hydroxy-6-methoxy-1,3-dimethylisochroman by catalytic hydrogenolysis followed by Fremy's salt oxidation of the derived phenol. The latter isochroman was synthesized from a mercury(II) mediated oxidative cyclization of (R)-3-benzyloxy-4-methoxy-1-(1'-hydroxyethyl)-2-prop-1'-enylbenzene which in turn was obtained in 75% ee from the chiral reduction of 1-acetyl-3-benzyloxy-4-methoxy-2-prop-1'-enylbenzene with borane-methylsulfide complex in the presence of the Corey-Bakshi-Shibata catalyst. (C) 2002 Elsevier Science Ltd. All rights reserved.
(1R,3R,4S)-3,4-二氢-4-羟基-6-甲氧基-1,3-二甲基异色烷-5,8-二酮是通过催化氢化从(1R,3R,4S)-5-苄氧基-3,4-二氢-4-羟基-6-甲氧基-1,3-二甲基异色烷合成而来,随后对衍生的酚进行弗雷米盐氧化,最终得到65%对映体过量率的产物。后者的异色烷是通过一种在水银(II)催化的氧化环化反应中制备的,起始材料为(R)-3-苄氧基-4-甲氧基-1-(1'-羟乙基)-2-烯基苯,该化合物是通过在Corey-Bakshi-Shibata催化剂存在下,利用硼氢化物-甲硫醚复合物对1-乙酰基-3-苄氧基-4-甲氧基-2-烯基苯进行手性还原得到的,其对映体过量率为75%。© 2002 Elsevier Science Ltd. 保留所有权利。