Regio- and stereoselective synthesis of 2-cyclopentenones via a hydrogenolysis-terminated Heck cyclization of β-alkylthio dienones
作者:Bangyu Liu、Gang Zheng、Xiaocui Liu、Cong Xu、Jingxin Liu、Mang Wang
DOI:10.1039/c3cc37571d
日期:——
Palladium-catalyzed cyclization of β-alkylthio dienone derivatives affords 2-cyclopentenones in a regio- and stereoselective manner in the presence of silane. CâS activation, intramolecular carbopalladation and hydrogenolysis construct the cascade process.
4-diamino-5-p-chlorophenyl-6-methylthio-pyrimidine (11) was prepared from 9c as a typical example using identifical conditions described for 7. The synthesis of 5,6-fused pyrimidines (14a–f), (19) and (23a–e) was also accomplished using the cyclic ketene-S,S-acetals (13a–c) and (22a–b). The present method is found to be more convenient and efficient than reported methods for alkoxy and methylthiopyrimidines
酮醇-S,S-乙缩醛(5a–c)在醇性钠的醇盐存在下与胍和硫脲反应,得到2-氨基和2-巯基-4-烷氧基-5-芳基-6-甲基-吡啶二酰亚胺(6a–k)分别以良好的收成。α-氰基碳烯-S,S-乙缩醛(9a–d)同样产生了带有胍的5-取代的2,4-二氨基-6-烷氧基-吡啶亚胺(10a-e),总收率为50-60%。未交换的2,4-二氨基-5- p -氯苯基-6-甲硫基嘧啶(11)制备图9c为使用用于描述identifical条件的典型例子7。5,6-稠合嘧啶的合成(14a–f),(19)和(23a–e)也使用环状乙烯酮-S,S-缩醛(13a–c)和(22a–b)完成。发现本方法比报道的烷氧基和甲硫基嘧啶的方法更方便和有效。
Pd-Catalyzed C–S Activation/Isocyanide Insertion/Hydrogenation Enables a Selective Aerobic Oxidation/Cyclization
作者:Jian Chang、Bangyu Liu、Yang Yang、Mang Wang
DOI:10.1021/acs.orglett.6b01780
日期:2016.8.19
isocyanides endows an unprecedented aerobicoxidation process. Catalyzed by Pd(Ph3P)2Cl2 in the presence of Ph3SiH under N2 then upon exposure to air, a wide range of α-acyl ketene dithioacetals react with isocyanides to afford 5-hydroxy-α,β-unsaturated γ-lactams via a C–S bond activation, isocyanide migratory insertion, hydrogenation, selectiveaerobicoxidation, and intramolecular nucleophilic addition
Tandem [3+1+1+1] Heterocyclization of α‐Acyl Ketene Dithioacetals with Ammonia and Methanol: Rapid Assembly of Polysubstituted Pyrimidines
作者:Youkun Wang、Linlin Yan、Xiaoxuan Zhang、Fengrui Xiang、Xiaojun Li、Shengnan Li、Xiaoning Song
DOI:10.1002/ejoc.202200237
日期:2022.4.21
An expeditious [3+1+1+1] heterocyclization of α-acyl ketene dithioacetals and renewable methanol as well as economical NH4OAc is established to construct densely functionalized pyrimidine derivatives. The domino conversion proceeds effectively through sequential keto imination/C−S aminolysis/cyclocondensation/dehydroaromatization processes under O2 atmosphere by harnessing the dual activities of CuCl2
Synthesis of Furfural Sulfides and 4‐Alkylthiopyridines <i>via</i> Heterocyclization of α‐Acyl Ketene Dithioacetals
作者:Xiaoxuan Zhang、Jian Chang、Chong Chen、Qianqian Zhai、Shengnan Li、Xiaoning Song
DOI:10.1002/adsc.202300574
日期:2023.11.7
Herein, we devised a synthetic approach for skeletally diversified furfuryl sulfides and 4-alkylthiopyridines involving the heterocyclization of flexible α-acyl ketene dithioacetals, enabled by cooperative Pd/Cu catalysis. The overall transformation was initiated by acyl-directed desulfurative Sonogashira coupling, which was proposed as the key step in surmounting the competitive carbothiolation pathway