Synthesis of (2S,4S,5S)-5-hydroxy-4-methylpipecolic acid via amide methylenation of 5-hydroxy-4-methyl-2-piperidinone with dimethyltitanocene
作者:Claus Herdeis、Eberhard Heller
DOI:10.1016/s0957-4166(97)00091-8
日期:1997.4
(4S,5S)-5-hydroxy-4-methylpiperidine-2-one 4, readily available from S-glutamic acid, serves as a starting material for the synthesis of (2S,4S,SS)-5-hydroxy-4-methylpipecolic acid 12. The key step of this reaction sequence is the chemoselective methylenation of the amide carbonyl group of 6 with dimethyltitanocene to the exocyclic enecarbamate 7. Hydroboration/oxidation of the double bond resulted in the formation of all-cis alcohol 8 which was transformed via aldehyde to 12. (C) 1997 Elsevier Science Ltd.
(S)-5-羟基-4-甲基吡咯烷-2-酮(4),可从S-谷氨酸方便获得,用作合成(2S,4S,5S)-5-羟基-4-甲基哌啶羧酸(12)的起始材料。此反应序列的关键步骤是利用二甲基钛ocene对酰胺羰基化合物6进行选择性甲基烯丙基化,生成外环烯丙酰胺7。通过双键的水合溶解/氧化,形成了全顺式醇8,随后经醛转化得到12。©1997 Elsevier Science Ltd.