کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5278865 | 1385613 | 2005 | 5 صفحه PDF | دانلود رایگان |
Enantioenriched aldol products derived from enones are notoriously difficult to prepare due to their sensitivity to retro-aldolisation, elimination and the requirement of a large excess of the enone donor for their preparation. However, some success has been obtained for the preparation of aldol products derived from methylvinylketone and pentenone using zinc-dinuclear catalysts or catalytic antibodies. Herein, we describe how simple first-generation hydroxyenones can be easily elongated by alkene exchange with structurally diverse olefinic partners in the presence of Ru-based metathesis catalysts allowing for the preparation of aldol products difficult to access by direct aldolisation. The data suggest that even though unprotected aldols are suitable for these cross-metathesis reactions, silyl-protected β-hydroxyenones generally afforded the desired elongated products in much higher chemical yields.
Journal: Tetrahedron Letters - Volume 46, Issue 50, 12 December 2005, Pages 8705-8709