描述了一种涉及将大二硫醇内酯桥接到双环系统的新反应。制备了一系列大二内酯并将其转化为必需的大二硫代内酯。后一种底物通过暴露于萘化钠而被诱导跨大环桥接,从而在加入甲基碘后形成稳定的双环系统。通过除去硫,将如此获得的混合硫缩酮转化为许多饱和或不饱和双环或多环系统。桥接的立体化学遵循顺式和反式产物的相对能量,而不是大环的构象偏好。MM2 计算和 X 射线晶体结构测定证实了这一点
is commercially available, is a practical and useful Lewis acidcatalyst for acylation of alcohols with acidanhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acidanhydrides of not only primary alcohols but also sterically-hindered secondary
Vielgliedrige heterocyclische Verbindungen VIII. Zur Kenntnis der hochgliedrigen Mono- und Poly-lȧctonringe
作者:M. Stoll、A. Rouvé
DOI:10.1002/hlca.193501801153
日期:——
1. Es wurde gezeigt, dass die der Veresterungsreaktion entgegenlaufende Verseifungsreaktion keine messbare Geschwindigkeit besitzt.
1.《世界经济日报》,《世界经济日报》。
Polymer-supported synthesis of series of macrocyclic oligoesters
作者:Manfred Rothe、Michael Zieger
DOI:10.1016/0040-4039(94)88413-7
日期:1994.11
ε-hydroxycaproic acid, resp., were attached to a cross-linked polystyrene by an activated ester bond. In the presence of strong tert. bases cyclo-oligomerization occurred on the resin yielding a series of macrocyclic rings which were isolated with up to 10 ω-hydroxy acid residues and 91 ring atoms.