已经研究了合成石松生物碱二氢番茄红素 ( 1 )的策略。合成路线是基于N-酰基吡啶盐化学开发的,以制备可最终收敛到天然产物的目标片段3和4。关键反应包括 IMDA 环加成和逆曼尼希开环以形成 AB 和 EF 环片段。使用吡啶取代和定向锂化化学制备环 C 前体。环 C 和 EF 的铃木交叉偶联导致 CEF 环片段。关闭七元 D 环的最初尝试没有成功。
已经研究了合成石松生物碱二氢番茄红素 ( 1 )的策略。合成路线是基于N-酰基吡啶盐化学开发的,以制备可最终收敛到天然产物的目标片段3和4。关键反应包括 IMDA 环加成和逆曼尼希开环以形成 AB 和 EF 环片段。使用吡啶取代和定向锂化化学制备环 C 前体。环 C 和 EF 的铃木交叉偶联导致 CEF 环片段。关闭七元 D 环的最初尝试没有成功。
Intramolecular diels-alder reactions of 2-alkenyl-1,2-dihydropyridines. An approach to the synthesis of the -decahydroquinoline ring system.
作者:Daniel L. Comins、Abdul H. Abdullah、Roy K. Smith
DOI:10.1016/s0040-4039(00)88002-8
日期:1983.1
In refluxing decalin 2-alkenyl-1-alkoxycarbonyl-1,2-dihydropyridines undergo an intramolecular Diels-Alder reaction to provide novel polycyclic compounds. The -decahydroquinoline ringsystem can be prepared from the appropriate Diels-Alder product utilizing a ring-opening reverse Mannich reaction.
An intramolecular Diels-Alder/retro-Mannich approach to the cis-perhydroquinoline ring system. Model studies toward the synthesis of Lycopodium alkaloids
作者:Daniel L. Comins、Rima S. Al-Awar
DOI:10.1021/jo00041a011
日期:1992.7
Model studies toward the preparation of cis-decahydroquinoline derivatives using an IMDA/retro-Mannich strategy were carried out. Tricyclic amino ester 13, prepared via an IMDA reaction of 1,2-dihydropyridine 11, was ring-opened on treatment with excess LDA. Trapping the intermediate dianion 17 with TMSCl gave the polysilylated derivatives 18. Subsequent N-acylation with benzyl chloroformate provided ene carbamate 19, which on catalytic hydrogenation gave the desired decahydroquinoline 21. In a similar manner, 1,2-dihydropyridine 22 was cyclized and ring-opened in two steps to give the desired cis-hexahydroquinolone 25. N-Acylation of 25 with LDA and benzyl chloroformate provided the benzyl carbamate 26 in quantitative yield. The target model compounds, 21 and 26, were prepared with complete control of relative stereochemistry at their three contiguous stereogenic centers. The mechanisms for the retro-Mannich ring-openings are discussed.
COMINS, D. L.;ABDULLAH, ABDUL, H.;SMITH, R. K., TETRAHEDRON LETT., 1983, 24, N 27, 2711-2714