Access to Spirocyclized Oxindoles and Indolenines via Palladium-Catalyzed Cascade Reactions of Propargyl Carbonates with 2-Oxotryptamines and Tryptamines
作者:Antoinette E. Nibbs、Thomas D. Montgomery、Ye Zhu、Viresh H. Rawal
DOI:10.1021/acs.joc.5b00277
日期:2015.5.15
through a process wherein the first nucleophilic unit on the oxindole or indole reacts with an allenyl-palladium species, formed from oxidative addition of Pd(0) to propargyl carbonates, to generate a π-allyl palladium intermediate that then reacts further with the second nucleophilic component of the oxindole or indole. The cascade process forges two bonds en route to spirocyclized oxindole and indolenine
Palladium-Catalyzed Modular Synthesis of Substituted Piperazines and Related Nitrogen Heterocycles
作者:Thomas D. Montgomery、Viresh H. Rawal
DOI:10.1021/acs.orglett.5b03708
日期:2016.2.19
We report here a novel method for the modular synthesis of highly substituted piperazines and related bis-nitrogen heterocycles via a palladium-catalyzed cyclization reaction. The process couples two of the carbons of a propargyl unit with various diamine components to provide nitrogen heterocycles in generally good to excellent yields and high regio- and stereochemicalcontrol.
propargyl carbonates have been developed by using two O-containing functional groups as the traceless assisting groups (AGs). The experimental investigations together with the density functional theory (DFT) calculations revealed that this transformation involves the free OH-directed cleavage of one terminal C–H bond of the alkenyl moiety and regioselective alkyne insertion, followed by OBoc-promoted intramolecular
Rhodium(III)-Catalyzed Oxadiazole-Directed Alkenyl C–H Activation for Synthetic Access to 2-Acylamino and 2-Amino Pyridines
作者:Fan Yang、Jiaojiao Yu、Yun Liu、Jin Zhu
DOI:10.1021/acs.joc.7b01303
日期:2017.10.6
We report herein a Rh(III)-catalyzed alkenyl C–H activation protocol for the coupling of oxadiazoles with alkynes and synthesis of 2-acylamino and 2-amino pyridines, an important heterocyclic scaffold for various naturals products and synthetic pharmaceuticals bearing a readily reacting functional group. The selective protection/deprotection of amino groups through simple solvent switching, good functional
Stereoselective synthesis of 3-spiropiperidino indolenines<i>via</i>S<sub>N</sub>2-type ring opening of activated aziridines with 1<i>H</i>-indoles/Pd-catalyzed spirocyclization with propargyl carbonates
作者:Sajan Pradhan、Chandan Kumar Shahi、Aditya Bhattacharyya、Manas K. Ghorai
DOI:10.1039/c8cc04249g
日期:——
3-Spiropiperidino indolenines have been synthesized via novel Lewis acid-catalyzed SN2-type ring opening of activated aziridines with 1H-indoles followed by Pd-catalyzed dearomative spirocyclization with propargyl carbonates in up to 88% yields. The step and pot-economic transformation comprises sequential C–C, C–N, and C–C bond forming steps generating two stereogenic centers including an all-carbon
通过新的路易斯酸催化具有1 H-吲哚的活化氮丙啶的S N 2型开环,然后用碳酸炔丙基酯进行Pd催化的脱芳香螺环化反应,合成了3-Spiropiperidino吲哚肾上腺素,产率高达88%。该步骤和罐区经济转型包括顺序的C–C,C–N和C–C键形成步骤,生成两个立体生成中心,包括全碳四元立体中心,以提供非对映体纯的形式(dr> 99:1)。具有出色的对映体过量(ee高达> 99%)。该策略的合成多功能性已通过将合成的产物转化为螺环吲哚啉2-哌啶酮,二氢哌啶和5-炔基哌啶来说明。