Synthesis of Tripyreno[2,3,4-abc: 2,3,4-ghi: 2,3,4-mno][18]annulenes
摘要:
The title compounds were prepared in a multi-step synthesis in which primarily the pyrene building blocks were formed (1.2 --> 11a.b). The final reaction step 11a,b --> 12a,b consisted of a threefold trans selective cyclocondensation process that generated the central 18-membered ring. Hexyl oxy or dodecyloxy sidechains attached on the periphery led to the formation of liquid crystalline phases.
描述了一种通过二酰亚胺还原策略合成α-取代的乙基膦酸酯的简单直接的方法。以K 3 PO 4或Na 2 CO 3为基本添加剂,在室温下,一定范围内的末端链烯基膦酸酯被2-硝基苯磺酰肼(NBSH)生成的二酰亚胺有效还原。还证明了该方法具有较高的官能团耐受性。此外,我们的方法具有安全性高,反应条件温和,对设备的要求低以及化学选择性高的特点。
A simple and straightforward method for the synthesis of α-substituted ethylphosphonates via diimide reduction strategy is described. With K3PO4 or Na2CO3 as the basic additive, a range of terminal alkenylphosphonates underwent efficient reduction by diimide generated from 2-nitrobenzenesulfonylhydrazide (NBSH) under room temperature. The high functional group tolerance of this methodology is also
描述了一种通过二酰亚胺还原策略合成α-取代的乙基膦酸酯的简单直接的方法。以K 3 PO 4或Na 2 CO 3为基本添加剂,在室温下,一定范围内的末端链烯基膦酸酯被2-硝基苯磺酰肼(NBSH)生成的二酰亚胺有效还原。还证明了该方法具有较高的官能团耐受性。此外,我们的方法具有安全性高,反应条件温和,对设备的要求低以及化学选择性高的特点。
The title compounds were prepared in a multi-step synthesis in which primarily the pyrene building blocks were formed (1.2 --> 11a.b). The final reaction step 11a,b --> 12a,b consisted of a threefold trans selective cyclocondensation process that generated the central 18-membered ring. Hexyl oxy or dodecyloxy sidechains attached on the periphery led to the formation of liquid crystalline phases.
Efficient synthesis of α-substituted ethylphosphonates via CuH-catalyzed conjugate reduction of terminal alkenylphosphonate
An unprecedented approach toward synthesis of α-substituted ethylphosphonates based on CuH-catalyzed conjugate reduction of vinylphosphonates has been successfully developed. This protocol features mild conditions, broad substrate scope, good functional group compatibility, high overall efficiencies, and easy gram-scale synthesis. The Cu-catalyzed reduction takes place in a highly selective manner