First General Approach to Cyclohex-3-ene-1,1-bis(phosphonates) by Diels−Alder Cycloaddition of Tetraethyl Vinylidenebis(phosphonate) to 1,3-Dienes
作者:Renzo Ruzziconi、Giacomo Ricci、Antimo Gioiello、Hélène Couthon-Gourvès、Jean-Philippe Gourvès
DOI:10.1021/jo0205154
日期:2003.2.1
Tetraethyl vinylidenebis(phosphonate) (VBP) reacts smoothly with substituted 1,3-dienes at 90-110 degrees C without solvent to give the corresponding cyclohex-3-ene-1,1-bis(phosphonates) in good yields (60-85%). With nonsymmetrically substituted dienes, mixtures of regioisomers are obtained, the regioisomeric ratio being exclusively controlled by electronic effects. Danishefsky's diene allows tetraethyl
在没有溶剂的情况下,四乙基亚乙烯基双(膦酸酯)(VBP)与取代的1,3-二烯在90-110摄氏度下平稳反应,以高收率(60-85)得到相应的环己-3-烯-1,1-双(膦酸酯) %)。使用非对称取代的二烯,获得区域异构体的混合物,区域异构体比率仅受电子效应控制。Danishefsky的二烯可在Diels-Alder环加合物经酸催化水解后,以81%的总收率获得4-氧代环己-2-烯-1,1-双(膦酸酯)四乙酯。与2,3-二甲氧基-1,3-丁二烯一起,通过正常的Diels-Alder环加合物的VBP催化的异构化反应,形成区域异构体二甲氧基环己烯-1,1-双(膦酸酯)的混合物。混合物会聚成3,4-二甲氧基环己基-2-烯-1四乙基,