Suzuki Keisuke, Nakata Tadashi
Graduate School of Science and Engineering, Saitama University, Japan.
Org Lett. 2002 Aug 8;4(16):2739-41. doi: 10.1021/ol026261q.
[reaction: see text] Stereoselective convergent synthesis of a trans-fused 6-6-6-6-membered tetracyclic ether ring system including 4alpha- or 4beta-hydroxy-5-methyl-tetrahydropyran was achieved. The key reactions involve the acetylide-aldehyde coupling of two tetrahydropyrans, intramolecular hetero-Michael cyclization of enone, stereoselective reduction of enone, hydroboration, intramolecular acetalization, and stereoselective reduction of the acetal with Et(3)SiH-TMSOTf.
[反应：见正文] 实现了包含4α-或4β-羟基-5-甲基-四氢吡喃的反式稠合6-6-6-6元四环醚环系统的立体选择性汇聚合成。关键反应包括两个四氢吡喃的乙炔化物-醛偶联、烯酮的分子内杂迈克尔环化、烯酮的立体选择性还原、硼氢化、分子内缩醛化以及用Et(3)SiH-TMSOTf对缩醛进行立体选择性还原。
