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Debabrata Maiti - One of the best experts on this subject based on the ideXlab platform.
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detailed mechanistic studies on palladium catalyzed selective c h Olefination with aliphatic alkenes a significant influence of proton shuttling
Journal of the American Chemical Society, 2017Co-Authors: Arghya Deb, Avijit Hazra, Qian Peng, Robert S Paton, Debabrata MaitiAbstract:Directing group-assisted regioselective C–H Olefination with electronically biased olefins is well studied. However, the incorporation of unactivated olefins has remained largely unsuccessful. A proper mechanistic understanding of Olefination involving unactivated alkenes is therefore essential for enhancing their usage in future. In this Article, detailed experimental and computational mechanistic studies on palladium catalyzed C–H Olefination with unactivated, aliphatic alkenes are described. The isolation of Pd(II) intermediates is shown to be effective for elucidating the elementary steps involved in catalytic Olefination. Reaction rate and order determination, control experiments, isotopic labeling studies, and Hammett analysis have been used to understand the reaction mechanism. The results from these experimental studies implicate β-hydride elimination as the rate-determining step and that a mechanistic switch occurs between cationic and neutral pathway. Computational studies support this interpret...
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Incorporating Unbiased, Unactivated Aliphatic Alkenes in Pd(II)-Catalyzed Olefination of Benzyl Phosphonamide
2017Co-Authors: Kapileswar Seth, Soumitra Agasti, Milan Bera, Massimo Brochetta, Ashis Das, Andrea Gandini, Alessio Porta, Giuseppe Zanoni, Debabrata MaitiAbstract:The use of unbiased aliphatic alkene as the coupling partner for C–H Olefination continues to be a challenging task. A suitable chelating directing group allowed ortho C–H Olefination of benzyl phosphonamide with unactivated aliphatic alkenes. The broad substrate scope with respect to variation of benzyl phosphonamides and aliphatic alkenes as well as examples of sequential hetero-bis-Olefinations offer diversity along with excellent linear/branch selectivity
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sequential meta c h Olefination of synthetically versatile benzyl silanes effective synthesis of meta olefinated toluene benzaldehyde and benzyl alcohols
Chemical Communications, 2016Co-Authors: Tuhin Patra, Rahul A Watile, Soumitra Agasti, Togati Naveen, Debabrata MaitiAbstract:Tremendous progress has been made towards ortho-selective C–H functionalization in the last three decades. However, the activation of distal C–H bonds and their functionalization has remained fairly underdeveloped. Herein, we report sequential meta-C–H functionalization by performing selective mono-Olefination and bis-Olefination with late stage modification of the C–Si as well as Si–O bonds. Temporary silyl connection was found to be advantageous due to its easy installation, easy removal and wide synthetic diversification.
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meta selective arene c h bond Olefination of arylacetic acid using a nitrile based directing group
ChemInform, 2015Co-Authors: Milan Bera, Tuhin Patra, Atanu Modak, Arun Maji, Debabrata MaitiAbstract:Phenylacetic acids (I) and (V) having a 2-hydroxybenzonitrile substituent as directing group undergo meta-selective Olefination with acrylates and vinyl ketones.
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Palladium-Catalyzed Aryl C–H Olefination with Unactivated, Aliphatic Alkenes
2014Co-Authors: Arghya Deb, Sukdev Bag, Rajesh Kancherla, Debabrata MaitiAbstract:Palladium-catalyzed coupling between aryl halides and alkenes (Mizoroki–Heck reaction) is one of the most popular reactions for synthesizing complex organic molecules. The limited availability, problematic synthesis, and higher cost of aryl halide precursors (or their equivalents) have encouraged exploration of direct Olefination of aryl carbon–hydrogen (C–H) bonds (Fujiwara–Moritani reaction). Despite significant progress, the restricted substrate scope, in particular noncompliance of unactivated aliphatic olefins, has discouraged the use of this greener alternative. Overcoming this serious limitation, we report here a palladium-catalyzed chelation-assisted ortho C–H bond Olefination of phenylacetic acid derivatives with unactivated, aliphatic alkenes in good to excellent yields with high regio- and stereoselectivities. The versatility of this operationally simple method has been demonstrated through drug diversification and sequential C–H Olefination for synthesizing divinylbenzene derivatives
Teckpeng Loh - One of the best experts on this subject based on the ideXlab platform.
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oxidant free rh iii catalyzed direct c h Olefination of arenes with allyl acetates
ChemInform, 2013Co-Authors: Chao Feng, Daming Feng, Teckpeng LohAbstract:A novel cationic Rh(III)-catalyzed Olefination of N,N-dialkylbenzamides with allylic acetates is developed to give trans-olefins in good yields.
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oxidant free rh iii catalyzed direct c h Olefination of arenes with allyl acetates
Organic Letters, 2013Co-Authors: Chao Feng, Daming Feng, Teckpeng LohAbstract:Rh(III)-catalyzed direct Olefination of arenes with allyl acetate via C–H bond activation is described using N,N-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of trans-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C–H Olefination.
Chao Feng - One of the best experts on this subject based on the ideXlab platform.
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oxidant free rh iii catalyzed direct c h Olefination of arenes with allyl acetates
ChemInform, 2013Co-Authors: Chao Feng, Daming Feng, Teckpeng LohAbstract:A novel cationic Rh(III)-catalyzed Olefination of N,N-dialkylbenzamides with allylic acetates is developed to give trans-olefins in good yields.
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oxidant free rh iii catalyzed direct c h Olefination of arenes with allyl acetates
Organic Letters, 2013Co-Authors: Chao Feng, Daming Feng, Teckpeng LohAbstract:Rh(III)-catalyzed direct Olefination of arenes with allyl acetate via C–H bond activation is described using N,N-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of trans-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C–H Olefination.
Ken Tanaka - One of the best experts on this subject based on the ideXlab platform.
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oxidative Olefination of anilides with unactivated alkenes catalyzed by an electron deficient η5 cyclopentadienyl rhodium iii complex under ambient conditions
Chemistry: A European Journal, 2015Co-Authors: Yuji Takahama, Yu Shibata, Ken TanakaAbstract:The oxidative Olefination of sp(2) C-H bonds of anilides with both activated and unactivated alkenes using an (electron-deficient η(5) -cyclopentadienyl)rhodium(III) complex is reported. In contrast to reactions using this electron-deficient rhodium(III) catalyst, [Cp*RhCl2 ]2 showed no activity against Olefination with unactivated alkenes. In addition, the deuterium kinetic isotope effect (DKIE) study revealed that the C-H bond cleavage step is thought to be the turnover-limiting step.
Daming Feng - One of the best experts on this subject based on the ideXlab platform.
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oxidant free rh iii catalyzed direct c h Olefination of arenes with allyl acetates
ChemInform, 2013Co-Authors: Chao Feng, Daming Feng, Teckpeng LohAbstract:A novel cationic Rh(III)-catalyzed Olefination of N,N-dialkylbenzamides with allylic acetates is developed to give trans-olefins in good yields.
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oxidant free rh iii catalyzed direct c h Olefination of arenes with allyl acetates
Organic Letters, 2013Co-Authors: Chao Feng, Daming Feng, Teckpeng LohAbstract:Rh(III)-catalyzed direct Olefination of arenes with allyl acetate via C–H bond activation is described using N,N-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of trans-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C–H Olefination.