Gold-Catalyzed Cyclization of O-Propargyl Carbamates under Mild Conditions: A Convenient Access to 4-Alkylidene-2-oxazolidinones.

ChemInform ◽  
2007 ◽  
Vol 38 (15) ◽  
Author(s):  
Stefanie Ritter ◽  
Yoshikazu Horino ◽  
Johann Lex ◽  
Hans-Guenther Schmalz
Keyword(s):  
Mild Conditions ◽  
Convenient Access

Highly selective difluoromethylations of β-keto amides with TMSCF2Br under mild conditions

Synlett ◽  
2021 ◽  
Author(s):  
yakun wang ◽  
Shuaifei Wang ◽  
Conghui Zhang ◽  
Ting Zhao ◽  
Yanqin Hu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Amino Alcohol ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Mild Conditions ◽  
Convenient Access

Without employing any transition metal and other additives, efficient methods for selective difluoromethylations of β-keto amides with TMSCF2Br reagent have been developed under mild conditions. This protocol allows a convenient access to various α-difluoromethyl β-keto amides with excellent yields (up to 93%) and high C/O regioselectivities (up to 99:1). The C/O selectivity of β-keto amides could be easily reversed and controlled by simply changing the base. This protocol can be easily scaled up and the C-difluoromethylation product could be reduced into CF2H contained amino-alcohol derivatives. Moreover, the first enantioselective electrophilic difluoromethylation of β-keto amides has been achieved by phase-transfer catalysis.

scholarly journals Highly selective difluoromethylations of β-keto amides with TMSCF2Br under mild conditions

2021 ◽  
Author(s):  
Yakun Wang ◽  
Shuaifei Wang ◽  
Conghui Zhang ◽  
Ting Zhao ◽  
Yanqin Hu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Amino Alcohol ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Mild Conditions ◽  
Convenient Access

Without employing any transition metal and other additives, efficient methods for selective difluoromethylations of β-keto amides with TMSCF2Br reagent have been developed under alkaline and open-air conditions. This protocol allows a convenient access to various α-difluoromethyl β-keto amides with excellent yields (up to 93%) and high C/O regioselectivities (up to 99:1). The C/O selectivity of β-keto amides could be easily reversed and controlled by simply changing the base. This protocol can be easily scaled up and the C-difluoromethylation product could be reduced into amino-alcohol derivatives. Moreover, the first enantioselective electrophilic difluoromethylation of β-keto amides has been achieved by phase-transfer catalysis.

Gold-Catalyzed Cyclization of O-Propargyl Carbamates under Mild ­Conditions: A Convenient Access to 4-Alkylidene-2-oxazolidinones

Synlett ◽  
2006 ◽  
Vol 2006 (19) ◽  
pp. 3309-3313 ◽  
Author(s):  
Hans-Günther Schmalz ◽  
Stefanie Ritter ◽  
Yoshikazu Horino ◽  
Johann Lex
Keyword(s):  
Mild Conditions ◽  
Convenient Access

Nucleophilic addition of tertiary propargylic amines to arynes followed by a [2,3]-sigmatropic rearrangement

2018 ◽  
Vol 54 (47) ◽  
pp. 6036-6039 ◽  
Author(s):  
Meng-Guang Zhou ◽  
Rui-Han Dai ◽  
Shi-Kai Tian
Keyword(s):  
Nucleophilic Addition ◽  
Conjugated Dienes ◽  
Sigmatropic Rearrangement ◽  
Mild Conditions ◽  
Convenient Access

Treatment of tertiary propargylic amines with 2-(trimethylsilyl)aryl triflates under mild conditions provides convenient access to amino-substituted allenes or conjugated dienes.

Palladium-catalyzed carbonylative transformation of aryl iodides and sulfonyl chlorides: convenient access to thioesters

2020 ◽  
Vol 7 (6) ◽  
pp. 885-889 ◽  
Author(s):  
Xinxin Qi ◽  
Zhi-Peng Bao ◽  
Xiao-Feng Wu
Keyword(s):  
Sulfonyl Chlorides ◽  
Aryl Iodides ◽  
Palladium Catalyzed ◽  
Convenient Access

A palladium-catalyzed carbonylative transformation of aryl iodides and sulfonyl chlorides to thioesters has been studied.

The Diorgano Dichalcogenides Addition to Benzyne under Mild Conditions

2007 ◽  
Author(s):  
Fabiano Toledo ◽  
Henrique Marques ◽  
João Comasseto ◽  
Cristiano Raminelli
Keyword(s):  
Mild Conditions

Pt-Pd Nanoalloy for the Unprecedented Activation of Carbon-Fluorine Bond at Low Temperature

2019 ◽  
Author(s):  
Raghu Nath Dhital ◽  
keigo nomura ◽  
Yoshinori Sato ◽  
Setsiri Haesuwannakij ◽  
Masahiro Ehara ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Dft Calculations ◽  
Bond Activation ◽  
Mild Conditions ◽  
Selective Transformation ◽  
Rate Determining Step ◽  
Highly Active ◽  
Harsh Conditions ◽  
Reaction Profile

Carbon-Fluorine (C-F) bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that often required harsh conditions. The alloying of Pt with Pd is crucial to activate C-F bond. The reaction profile kinetics revealed that the major source of hydrogen in the defluorinated product is the alcoholic proton of 2-propanol, and the rate-determining step is the reduction of the metal upon transfer of the <i>beta</i>-H from 2-propanol. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

2020 ◽  
Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer
Keyword(s):  
Wittig Reaction ◽  
Condensation Reaction ◽  
Synthetic Methods ◽  
Anthracene Derivative ◽  
Double Ring ◽  
Mild Conditions ◽  
Wide Range ◽  
Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

SuFEx Activation with Ca(NTf2)2: A Unified Strategy to Access Sulfamides, Sulfamates and Sulfonamides from S(VI) Fluorides

2020 ◽  
Author(s):  
Subham Mahapatra ◽  
Cristian P. Woroch ◽  
Todd W. Butler ◽  
Sabrina N. Carneiro ◽  
Sabrina C. Kwan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Medicinal Chemistry ◽  
Mild Conditions ◽  
Broad Array

<p><br></p> <p>A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide, and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight the application of this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds. </p>

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