1,5-Stereocontrol in tin(IV) halide promoted reactions of 2-alkoxy-1-(2-tributylstannylethylidene)cyclohexanes with aldehydes
作者:Poonam Kumar、Eric J. Thomas、Daniel Tray
DOI:10.1016/j.tet.2007.03.070
日期:2007.7
2-Methoxy- and 2-(p-methoxybenzyloxy)-1-(2-tributylstannylethylidene)cyclohexanes 22 and 23 were prepared from 2-methoxy- and 2-(p-methoxybenzyloxy)cyclohexanones 12 and 13. The allylstannane 22 was transmetallated stereoselectively with tin(IV) chloride at −78 °C to generate an allyltin trihalide, which reacted with aldehydes to give (Z)-(3-hydroxyalkylidene)-2-methoxycyclohexanes 24 with excellent
2-甲氧基和2-(p -methoxybenzyloxy)-1-(2- tributylstannylethylidene)环己烷22和23,从2-甲氧基-和2-制备(p -methoxybenzyloxy)的环己酮12和13。所述allylstannane 22在-78℃下用氯化锡立体选择性transmetallated以产生三卤化烯丙基锡,其与醛反应,得到(Ž) - (3-hydroxyalkylidene)-2- methoxycyclohexanes 24具有优良的1,5-顺式-立体控制。观察到的2-(与醛的类似反应p -methoxybenzyloxy)取代allylstannane 23。由对硝基苯甲醛制备的产物24f的结构通过对其对硝基苯甲酸酯27的X射线结构测定来证实。