Tetrahedron

Olefin cyclisations of hindered α-acyliminium ions

BP Wijnberg, WN Speckamp, ARC Oostveen

文献索引：Wijnberg, B. P.; Speckamp, W. N.; Oostveen, A. R. C. Tetrahedron, 1982 , vol. 38, # 1 p. 209 - 217

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被引用次数: 22

摘要

Stereocontrolled NaBH4/H⊕-reduction of 3, 4-cis-disubstituted N-alkenyl imides 1–5 leads to secondary hydroxylactams. Tertiary hydroxylactams are formed via addition of MeMgCl to imides 2 and 4. HCOOH-Cyclisation of the hydroxylactams affords polycyclic piperidines through stereoselective α-acyliminium ring closure. Concomitant synchronous and stepwise cyclisation pathways are operative in the anti-periplanar addition of tertiary α-acyliminium ...