Synthesis of 2,4-Furanophanes by Palladium-Catalyzed Macrocyclization Reactions of 1,n-Diallenyl Diketones
作者:A. Stephen K. Hashmi、Lothar Schwarz、Michael Bolte
DOI:10.1002/ejoc.200300792
日期:2004.5
The 1,n-diallenyl diketones 8a−j were prepared and subjected to reactions with the [PdCl2(MeCN)2] catalyst. Upon decreasing the length of the bridge between the allenyl ketone units, first we obtained the (E) isomer 10 as the macrocyclic product and then the (Z) isomer 11 accompanied by the exocyclic double bond isomer 12. In all cases, the open-chained 1,n-difuryl alkanes were isolated as side-products
制备 1,n-二烯基二酮 8a-j 并使其与 [PdCl2(MeCN)2] 催化剂反应。在减少丙二烯基酮单元之间的桥的长度后,首先我们得到 (E) 异构体 10 作为大环产物,然后得到 (Z) 异构体 11 和环外双键异构体 12。在所有情况下,开环-链状 1,n-二呋喃烷烃作为副产物被分离出来。具有更长桥连和醚官能团的二烯基二酮 19 和 24 的类似制备和转化产生了 20 至 52 元大环 21a、21b、26a 和 26b,仅具有预期的 (E) 构型双键。呋喃衍生物的闭环,在其 2-和 4-位的取代基中具有乙烯基,通过 Ru 催化的烯烃复分解反应生成相关产物,其产率类似于 Pd 催化的大环化,但提供了两种双键异构体的混合物。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)