Ruthenium‐Catalyzed Oxidative Transformations of Terminal Alkynes to Ketenes By Using Tethered Sulfoxides: Access to β‐Lactams and Cyclobutanones

Wang, Youliang; Zheng, Zhitong; Zhang, Liming

doi:10.1002/ange.201403796

Cited by 9 publications

(2 citation statements)

References 40 publications

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“…The reaction proceeds via the generation of rhodium ketene species directly from terminal alkynes by oxidation of vinylidene rhodium species 3. Similarly there are several reports from other groups for the ruthenium‐catalyzed oxidation of terminal alkynes to ketenes, for example, with flexibly tethered sulfoxides as internal oxidants and their reactions with imines 4. There are almost no reports in the literature on the [2+2] cycloaddition reaction of terminal alkynes and imines via in situ generation of allene type intermediates.…”

Section: Preliminary Screening Of the Reaction Conditions For The Synmentioning

confidence: 99%

Einfluss der Nachbehandlung auf das Karbonatisierungsverhalten von Beton aus klinkerarmen Zementen

Hainer

Proske

Graubner

2015

Beton und Stahlbetonbau

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Influence of curing on the carbonation of clinker-reduced concretesThe durability of concrete structures is significantly influenced by the curing conditions. The normative required curing time of concrete elements is determined by the exposure class and the strength development of the concrete. This article deals with the influence of curing on the compressive strength and the carbonation depth of concretes with low clinker cements. As part of the experimental investigations, both the influence of the curing time and the effects of varying environmental conditions and a subsequent moistening on the concrete properties were analyzed. Furthermore, a comparison of the results with known prediction models on the influence of curing time and environmental conditions on the carbonation depth was carried out. Subsequently an evaluation of the required minimum curing time according to DIN 1045-3 [1] was conducted.

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Section: Preliminary Screening Of the Reaction Conditions For The Synmentioning

confidence: 99%

Einfluss der Nachbehandlung auf das Karbonatisierungsverhalten von Beton aus klinkerarmen Zementen

Hainer

Proske

Graubner

2015

Beton und Stahlbetonbau

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“…Cyclobutane derivatives are the important intermediates for the synthesis of natural products and drugs . In the past few decades, [2 + 2] cycloadditions promoted by various methods have been developed to access cyclobutane derivatives such as photocatalysis, acid catalysis, and transition metal catalysis . Despite progress, the practical and efficient methods are limited.…”

Section: Introductionmentioning

confidence: 99%

A computational study into the origin of reactivity and selectivity of organocatalyzed [2 + 2] reactions between α,β‐unsaturated aldehydes and nitroolefins

Dong

Zhang

et al. 2019

J of Physical Organic Chem

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The mechanisms of organocatalyzed [2 + 2] reactions between α,β‐unsaturated aldehydes and nitroolefins with various substituents were explored using the density functional theory M05‐2X method. The calculations indicate that all 14 reactions we studied proceed through a stepwise mechanism and most of them are predicted to be feasible both kinetically and thermodynamically. The feasibility of the catalyzed reactions is mainly attributed to that the formation of dienamines could significantly increase the highest occupied molecular orbital (HOMO) energy of α,β‐unsaturated aldehydes, while the substituents have less influence. Also, the H‐bonding interactions between the catalysts and nitroolefins play a key role in the regioselectivity, and the stronger H‐bond favors the 3,4‐reactivity. Besides, the chemoselectivity is also discussed.

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Metal‐Free Synthesis of Chlorinated β‐Amino Ketones via an Unexpected Reaction of Imines with Arylacetylenes in 1,1,1,3,3,3‐Hexafluoro‐2‐propanol

et al. 2015

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The metal‐free reaction of terminal arylacetylenes with α,α‐dichloroaldimines in 1,1,1,3,3,3‐hexafluoro‐2‐propanol as the sole solvent results in the rapid and selective formation of γ,γ‐dichloro‐β‐amino ketones. In this solvent the expected dichlorinated propargylamines and/or allylic amines are not formed. The dichloromethylene moiety of the aldimine acts as an activating group and is essential to accomplish this transformation. Electron‐rich acetylenes lead to the best results and work well with all imines (with or without α′‐H at the nitrogen substituent), while electron‐deficient acetylenes only reacted with N‐tert‐butylaldimines (no α′‐H). The mechanistic pathway showed 1,1,1,3,3,3‐hexafluoro‐2‐propanol to protonate the aldimine, which in the rate‐determining step will react with the arylacetylene to form a resonance‐stabilized allene cation, which is trapped by a HFIP molecule giving rise to an enol ether, which promptly hydrolyzes to furnish exclusively the β‐amino ketones. Using DFT techniques we found that the first CC bond forming step is the rate‐determining step and is associated with a barrier of about 21 kcal mol−1.magnified image

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Ruthenium‐Catalyzed Oxidative Transformations of Terminal Alkynes to Ketenes By Using Tethered Sulfoxides: Access to β‐Lactams and Cyclobutanones

Cited by 9 publications

References 40 publications

Einfluss der Nachbehandlung auf das Karbonatisierungsverhalten von Beton aus klinkerarmen Zementen

Einfluss der Nachbehandlung auf das Karbonatisierungsverhalten von Beton aus klinkerarmen Zementen

A computational study into the origin of reactivity and selectivity of organocatalyzed [2 + 2] reactions between α,β‐unsaturated aldehydes and nitroolefins

Metal‐Free Synthesis of Chlorinated β‐Amino Ketones via an Unexpected Reaction of Imines with Arylacetylenes in 1,1,1,3,3,3‐Hexafluoro‐2‐propanol

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