The reaction of different fluoroarenes 1 with lithium and a catalytic amount (7%) of naphthalene in THF at -30 degrees C affords the corresponding aryllithium intermediates which, by reaction with several electrophiles at temperatures ranging between -30 and 0 degrees C, lead to the expected products 2, after hydrolysis. (C) 2000 Elsevier Science Ltd. All rights reserved.
Efficiency of photochemical intramolecular and intermolecular cycloaddition of 9-phenanthrenecarboxylate-anethole systems is dependent on the structure of anethole moiety. Reduction in reactivity of the anethole moiety by steric effects is explained in terms of decrease in coefficients of frontier orbitals on the double bond due to twisting of the anisyl moiety.
Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
作者:Moshood O. Ganiu、Alexander H. Cleveland、Jarrod L. Paul、Rendy Kartika
DOI:10.1021/acs.orglett.9b01959
日期:2019.7.19
The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the
Verschiedene S-tert.-Aralkyl-Derivate des Cysteins (4a–g, 2a, b, 3a, 11, 12) wurden hergestellt. Sie lassen sich in bekannter Weise in Esterhydrochloride, in N-Benzyloxycarbonyl-, N-tert.-Butyloxycarbonyl- und N-Phthalyl-Verbindungen und deren aktivierte Ester, z. B. 4-Nitro-phenylester, überführen. Aus diesen Verbindungen können nach bekannten Methoden Peptide erhalten werden. Die selektive Entfernung
Verschiedene小号-叔芳烷基-衍生物DES半胱氨酸(图4a-G ,图2a,b,图3a,11,12)hergestellt wurden。SIE拉森SICH在bekannter魏泽在Esterhydrochloride,在Ñ苄氧基羰基,ñ -叔丁氧羰基UND Ñ -Phthalyl-Verbindungen UND得润aktivierte酯,Z。B. 4-硝基苯酯,überführen。Aus diesen Verbindungenkönnennach bekannten Methoden肽erhalten werden。选择性的Entfernung der N -Schutzgruppen手套HCl / Eisessig,HBr / Eisessig od Hydrazin istmöglich。模具neuen小号-Schutzgruppen合成碱和胺稳定剂;如果使用Abspaltung
Generation of Aryl and Heteroaryl Magnesium Reagents in Toluene by Br/Mg or Cl/Mg Exchange
作者:Dorothée S. Ziegler、Konstantin Karaghiosoff、Paul Knochel
DOI:10.1002/anie.201802123
日期:2018.5.28
very fast Br/Mgexchange with aryl and heteroaryl bromides, producing aryl and heteroaryl magnesium alkoxides (ArMgOR⋅LiOR) in toluene. These Grignard reagents react with a broad range of electrophiles, including aldehydes, ketones, allyl bromides, acyl chlorides, epoxides, and aziridines, in good yields. Remarkably, the related reagent sBu2Mg⋅2 LiOR (R=2‐ethylhexyl) undergoes Cl/Mgexchange with various
Unexpected formation of aryl dialkyl carbinol as a side product from the reaction of methoxyarylaldehydes with Grignard reagents
作者:Anuj Sharma、Bhupendra P. Joshi、Narendra P. Singh、Arun K. Sinha
DOI:10.1016/j.tet.2005.10.051
日期:2006.1
In the attempted formation of secondary aryl alkyl carbinols from the reaction of methoxyarylaldehydes with Grignard reagents, aryl dialkyl carbinols were formed as unexpected side products. A mechanism for their formation is proposed.