作者:Stéphanie Fréville、Martine Bonin、Jean-Pierre Célérier、Henri-Philippe Husson、Gérard Lhommet、Jean-Charles Quirion、Vu Moc Thuy
DOI:10.1016/s0040-4020(97)00525-5
日期:1997.6
(+) and (-) trans-2,6-dimethylpiperidines 9 have been prepared from diastereomeric lactams 6 and 11, both available from (R)-(-)-phenylglycinol 4. Diastereoselective C-2 alkylation afforded oxazolidines 7 and 12. Reduction of 7 with LiAlH4 or NaBH4 led to trans-2,6-8 with total retention of configuration; When 12 was reduced with NaBH4, irans derivative 13a was isolated as the major isomer. A mechanism is proposed to explain the different results. (C) 1997 Elsevier Science Ltd.
顺式和反式-2,6-二甲基哌啶9已从对映异构的内酰胺6和11制备,两者均可从(R)-(-)-苯甘醇4获得。通过选择性C-2烷基化得到了草酮衍生物7和12。当草酮衍生物7用氢化锂铝或钠硼氢还原时,得到反式-2,6-二甲基哌啶8,并完全保留了构型;当草酮衍生物12用钠硼氢还原时,得到反式-2,6-二甲基哌啶13a作为主要异构体。提出了一个机理来解释不同的结果。