The synthesis of 9-substituted N-benzyl-8-azabicyclo[4.3.0]non-4-en-7-ones by the intramolecular Diels–Alder reaction
作者:Roger Brettle、Iftikhar A. Jafri
DOI:10.1039/p19830000387
日期:——
The intramolecular thermal cyclisation of N-allyl-N-benzylpenta-2(E), 4-dienamide in refluxing NN-dimethylformamide gives N-benzyl-cis- and trans-8-azabicyclo[4.3.0]non-4-en-7-one; N-allyl-N-benzylhexa-2(E), 4(E)-dienamide gives (1RS, 3RS, 6SR)-3-methyl- and (1RS, 3RS, 6RS)-3-methyl-N-benzyl-8-azabicyclo[4.3.0]non-4-en-7-one. 9-Benzyl- and 9-isobutyl-N-benzyl-8-azabicyclo[4.3.0]-non-4-en-7-one are
的分子内环化热Ñ -allyl- Ñ -benzylpenta -2(É),4-二烯酰胺在回流的NN二甲基甲酰胺给出Ñ苄基顺式-和反式-8-氮杂双环[4.3.0]壬-4-烯7-1;N-烯丙基-N-苄基己二(E),4(E)-二酰胺产生(1 RS,3 RS,6 SR)-3-甲基-和(1 RS,3 RS,6 RS)-3-甲基- ñ -苄基-8-氮杂双环[4.3.0]壬-4-烯-7-酮。9-苄基和9-异丁基-N-苄基-8-氮杂双环[4.3.0]-非-4-en-7-one是通过适当的α-取代的N-烯丙基二-2(E),4-二酰胺的类似分子内热环化制备的。主要产品均具有顺式稠合环,但在每种情况下均形成所有可能的构型,包括具有反式稠合环的产品。双环产物的相对立体化学根据其高分辨率的1 H nmr光谱进行分配。