An unusual regiochemistry of reactions of a cyclohexenylphosphonate bearing a β-ethoxycarbonyl group with aldehydes
作者:Ewa Krawczyk、Krzysztof Owsianik
DOI:10.1016/j.tet.2011.01.016
日期:2011.3
with α or δ regioselectivity. Such an unusual regioselectivity results from the contribution of two allylic carbanions: one, stabilized by the phosphonate moiety and the other stabilized by the carboethoxy group. The course of the reaction depends mainly on the structure of the aldehyde and the reaction conditions. The products of Horner–Wadsworth–Emmons reaction, including an analogue of some retinol
研究了锂化的6-(二甲氧基磷酰基)环己-1-烯甲酸乙酯与脂族,芳族和不饱和醛的反应,并确定其以α或δ区域选择性进行。这种不寻常的区域选择性是由两种烯丙基碳负离子的作用引起的:一种由膦酸酯部分稳定,而另一种则由碳乙氧基稳定。反应过程主要取决于醛的结构和反应条件。Horner-Wadsworth-Emmons反应的产物,包括一些视黄醇代谢产物的类似物,是在动力学条件下形成的,而δ加合物则是热力学产物。