以前未开发的将格利雅(Grignard)添加到羟吲哚中的方法通过一锅芳构化驱动的脱水途径,以高收率提供了一种区域特异性的方法,用于2-和2,3-二取代的吲哚衍生物。这种方法可以方便地制备用作烯丙基[1,2- a ]吲哚和咔唑的正交合成的闭环复分解(RCM)前体的二烯丙基吲哚。该方法的合成效用通过微管蛋白抑制剂和天然存在的咔唑生物碱的合成来说明。
Palladium catalyzed divergent cycloadditions of vinylidenecyclopropane-diesters with methyleneindolinones enabled by zwitterionic π-propargyl palladium species
作者:Ben Niu、Yin Wei、Min Shi
DOI:10.1039/d1cc01453f
日期:——
spirooxindoles fused with a five- or a six-membered ring by a cycloaddition reaction of vinylidenecyclopropane-diesters with methyleneindolinones was disclosed. This protocol features an in situ generated unprecedented zwitterionic π-propargyl palladium species in cycloaddition reactions and a switchable process between (3+2) and (4+2) cycloadditions by changing the phosphine ligand.
A catalyticenantioselective Strecker reaction of isatin-derived N-unsubstituted ketimines directly afforded the N-unprotected α-aminonitriles with a tetrasubstituted carbon stereocenter in up to 99% ee without requiring protection/deprotection steps. One-pot Strecker reactions from the parent carbonyl compounds were also realized with comparable yields and enantioselectivities. Direct transformations
Lewis Acid-Catalyzed Malonate Addition onto 3-Hydroxy-2-oxindoles: Mechanistic Consideration and Synthetic Approaches to the Pyrroloindoline Alkaloids
作者:K. Naresh Babu、Nikhil Raj Kariyandi、Saina Saheeda M. K.、Lakshmana K. Kinthada、Alakesh Bisai
DOI:10.1021/acs.joc.8b02017
日期:2018.10.19
Metal triflate-catalyzed reactions of 3-hydroxy-2-oxindoles with a variety of malonates have been developed under mild conditions. The reaction afford a variety of 2-oxindoles sharing a C-3 quaternary center at the pseudobenzylic position in an operationally simple procedure. Control experiments using enantioenriched 3-hydroxy/methoxy 2-oxindoles (91% ee) afforded a malonate addition product in racemic
Indium-mediated Palladium-catalyzed Allylic Alkylation of Isatins with Alkynes
作者:Zijun Wu、Xinxin Fang、Yuning Leng、Hequan Yao、Aijun Lin
DOI:10.1002/adsc.201701139
日期:2018.3.20
An unprecedented indium‐mediated palladium‐catalyzed allylic alkylation of isatins with alkynes is disclosed. This reaction provides a new, practical, and straightforward route to access 3‐allyl‐3‐hydroxy‐2‐oxindoles in good yields with broad substrate scope and scalability, exhibiting high atom and step economy. A primary mechanistic study reveals that indium played two roles in the reaction, first
base-promoted homolytic aromatic substitution. This novel cascade reaction provides a straightforward approach toward various naphtho-fused oxindoles from 2-halobenzaldehydes and indolin-2-ones in the presence of Cs2CO3 in DMSO. The enolates of indolin-2-ones as new and internal electron donors have been demonstrated to initiate intramolecular radical dehalogenative coupling.
通过将分子间的阿道尔顿缩合反应与随后的分子内碱基促进的均相芳族取代反应相结合,已经实现了一种不寻常的苯环化反应。这种新颖的级联反应为在DMSO中存在Cs 2 CO 3的情况下从2-卤代苯甲醛和吲哚-2-酮的各种萘稠合的吲哚提供了直接的方法。吲哚-2-酮作为新的和内部的电子供体的烯醇被证明可以引发分子内自由基脱卤偶联。