Preparation of (2E,4E)-2-(2-benzyloxyethyl)-5-(3-methoxy-4-chlorophenyl)penta-2,4-dienal as a key intermediate in the synthesis of strobilurin B
作者:V. A. Popovsky、A. V. Stepanov、N. Ya. Grigorieva
DOI:10.1007/s11172-012-0215-2
日期:2012.8
(2E,4E)-2-(2-Benzyloxyethyl)-5-(4-chloro-3-methoxyphenyl)penta-2,4-dienal was obtained by the condensation of 4-benzyloxybutanal N-tert-butylimine with 4-chloro-3-methoxycinnamic aldehyde with ≥98% configurational purity and 40% yield. When 4-benzyloxy-2-triethylsilylbutanal imine was used, a 7: 3 mixture of the target (2E,4E)-dienal with its (2Z,4E)-isomer was obtained in 60% yield; the latter quantitatively isomerized to the thermodynamically preferable target (2E,4E)-dienal.
通过4-苄氧基丁醛N-叔丁基亚胺与4-氯-3-甲氧基肉桂醛的缩合反应,获得了构型纯度≥98%、收率40%的(2E,4E)-2-(2-苄氧基乙基)-5-(4-氯-3-甲氧基苯基)戊-2,4-二烯醛。当使用4-苄氧基-2-三乙基硅基丁醛亚胺时,得到了目标(2E,4E)-二烯醛与其(2Z,4E)异构体的7:3混合物,收率为60%;后者定量异构化为热力学上更有利的目标(2E,4E)-二烯醛。