With Tag: General Organic Chemistry

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Catalytic Transamidation Reactions Compatible with Tertiary Amide Metathesis under Ambient Conditions

Nickeisha A. Stephenson, Samuel H. Gellman, Shannon S. Stahl, Jiang Zhu
J. Am. Chem. Soc. | 2009 | 10.1021/ja8094262

The carbon−nitrogen bond of carboxamides is extremely stable under most conditions. The present study reveals that simple zirconium− and hafnium−amido complexes are highly efficient catalysts for equilibrium-controlled transamidation reactions between...


Controlling Regiochemistry in Negishi Carboaluminations. Fine Tuning the Ligand on Zirconium

Tom Butler, Asher Lower, Bruce H. Lipshutz
J. Am. Chem. Soc. | 2006 | 10.1021/ja065769b

The species on the zirconocene catalyst is changed from two Cp's to the Brintzinger ligand and catalytic amounts of MAO are used to usually effect a >99% regiocontrol of Negishi carboaluminations of 1-alkynes in toluene.


A Comprehensive Approach to the Synthesis of Sulfate Esters

Theodore S. Widlanski, Levi S. Simpson
J. Am. Chem. Soc. | 2006 | 10.1021/ja056086j

A comprehensive approach to the synthesis of sulfate esters was developed. This approach permits the direct and high-yielding synthesis of protected sulfate monoesters. Subsequent deblocking to reveal sulfate monoesters is accomplished in near-quantitative...


Synthesis of Symmetrical Trisubstituted Olefins by Cross Metathesis

Robert H. Grubbs, Arnab K. Chatterjee, Daniel P. Sanders
Org. Lett. | 2002 | 10.1021/ol0259793

Trisubstituted alkenes have been prepared via intermolecular olefin cross-metathesis (CM) between α-olefins and symmetrically 1,1-disubstituted olefins using an imidazolylidene ruthenium benzylidene complex. Of particular interest is the synthesis of...


One-Pot (1-Ethoxycarbonylcyclopropyl)triphenylphosphonium Tetrafluoroborate Ring-Opening and Wittig Reaction

Jianmin Sun, Laura A. McAllister, Loren M. Price, Yue Shen, Mark S. Plummer, Joel T. Arcari, Justin I. Montgomery, Daniel P. Uccello, Seung Won Chung, Joseph A. Abramite, Robert M. Oliver
Org. Lett. | 2011 | 10.1021/ol202207f

An efficient method was developed for the synthesis of 2-methylene-4-substituted ethyl butyrates via cyclopropyl opening followed by a Wittig reaction. The desired products were formed in a two-step, one-pot reaction sequence. Alternatively, the key...


Asymmetric Hydrogenation of Alkynyl Ketones with the η6-Arene/TsDPEN–Ruthenium(II) Catalyst

Hironori Satoh, Noriyoshi Arai, Kunihiko Murata, Kunihiko Tsutsumi, Takeshi Ohkuma, Noriyuki Utsumi
Org. Lett. | 2013 | 10.1021/ol4012184

Enantioselective hydrogenation of alkynyl ketones catalyzed by Ru(OTf)(TsDPEN)(η 6 -p-cymene) (TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine) affords the propargylic alcohols in up to 97% ee. The alkynyl moieties are left intact in most cases....


Metal-Free Halonium Mediated Acetate Shifts of Ynamides To Access α-Halo Acrylamides/Acrylimides

Yann Odabachian, Zhuo Xin, Søren Kramer, Stig D. Friis, Troels Skrydstrup
Org. Lett. | 2011 | 10.1021/ol200269h

A metal-free acetate shift of 3-acetoxy ynamides to access α-iodo, bromo, and chloro acrylamides/acrylimides under very mild conditions is demonstrated. The inherent alkyne activation of ynamides is sufficient to ensure the α-halo acrylamides/acrylimides in...


Titanocene(II)-Promoted, One-Pot, Three-Component Coupling of Thioacetals, Alkynyl Sulfones, and Carbonyl Compounds:  Highly Stereoselective Formation of tert-Homopropargyl Alcohols

Takenori Sugita, Takeshi Takeda, Akira Tsubouchi, Maiko Ando
Org. Lett. | 2007 | 10.1021/ol071077w

Titanocene alkylidene complexes, generated by desulfurizative titanation of thioacetals with Cp 2 Ti[P(OEt) 3 ] 2 , reacted with alkynyl methyl sulfones to produce organotitanium species, which gave tert-homopropargyl alcohols with high diastereoselectivity...


Site-Selective Pd-Catalyzed Coupling of 1,4-Diiodo-1,3-alkadienes with Grignard Reagents and Its Application to the Synthesis of Fulvenes

Minoru Uemura, Yuuki Takayama, Fumie Sato
Org. Lett. | 2004 | 10.1021/ol0478032

The coupling reaction of 1,4-diiodo-1,3-alkadienes with a Grignard reagent in the presence of a catalytic amount of Pd(PPh 3 ) 4 proceeded with excellent site-selectivity. Synthetic application of the reaction was demonstrated by a regio- and stereoselective...


[1,5]-H Shift of Aldehyde Hydrogen in Dienal Compounds to Produce Ketenes

Taku Sakaguchi, Yohei Tsutsumi, Shigeo Katsumura, Hiroshi Tsuchikawa, Yudai Okuno
Org. Lett. | 2011 | 10.1021/ol2016302

In 3-ethoxycarbonyl-2,4-dienal compounds, a thermal [1,5]-H shift of aldehyde hydrogen easily proceeded to produce the corresponding vinyl ketenes due to the remarkable substituent effect caused by the C3 ester group. The produced ketenes were captured by an...


Selective Alkylation of (Hetero)Aromatic Amines with Alcohols Catalyzed by a Ruthenium Pincer Complex

Maud Lenormand, Santosh Agrawal, Belén Martín-Matute
Org. Lett. | 2012 | 10.1021/ol3001969

A readily available pincer ruthenium(II) complex catalyzes the selective monoalkylation of (hetero)aromatic amines with a wide range of primary alcohols (including pyridine-, furan-, and thiophene-substituted alcohols) with high efficiency when used in low...


Carbon Nucleophiles in the Mitsunobu Reaction. Mono- and Dialkylation of Bis(2,2,2-trifluoroethyl) Malonates

Alexei P. Leonov, James M. Takacs, Gregory C. Theriot, Xun-tian Jiang, Zhenrong Xu
Org. Lett. | 2002 | 10.1021/ol0266626

Simple dialkyl malonate esters, for example diethyl malonate, exhibit relatively limited scope as carbon nucleophiles in the Mitsunobu dehydrative alkylation reaction. In contrast, bis(2,2,2-trifluoroethyl) malonate readily undergoes dehydrative alkylation...


A Method for the Net Contra-thermodynamic Isomerization of Cyclic Trisubstituted Alkenes

Laurent Petit, Samir Z. Zard, Raphaël F. Guignard
Org. Lett. | 2013 | 10.1021/ol4018744

A simple sequence for the net contra-thermodynamic isomerization of cyclic trisubstituted alkenes is reported consisting of a radical addition of p-chlorothiophenol, followed by oxidation to the sulfoxide and thermal syn-elimination to give the least...


Preparation of syn-Tertiary Homoallylic Alcohols Utilizing Allenyltitanocenes Generated by Reductive Titanation of γ-Trimethylsilylpropargylic Carbonates

Takeshi Takeda, Akira Tsubouchi, Yasutaka Yatsumonji, Takenori Sugita
Org. Lett. | 2010 | 10.1021/ol100395n

syn-Tertiary homoallylic alcohols were obtained by the reaction of α-silylallenyltitanocenes generated by the reductive titanation of γ-silylpropargylic carbonates with Cp 2 Ti[P(OEt) 3 ] 2 with ketones and following desilylation and partial hydrogenation....


Enantioselective Nucleophilic Formylation and Cyanation of Conjugated Enones via Michael Addition of Formaldehyde SAMP-Hydrazone

Eloísa Martín-Zamora, Jose-María Lassaletta, Elena Díez, Rosario Fernández
J. Am. Chem. Soc. | 1996 | 10.1021/ja9610500



A Ru-Catalyzed Three-Component Addition To Form 1,5-Diketones

Moshe Portnoy, Hideki Kurihara, Barry M. Trost
J. Am. Chem. Soc. | 1997 | 10.1021/ja963460u



Asymmetric Synthesis of Trifluoromethylated Amines via Catalytic Enantioselective Isomerization of Imines

Yongwei Wu, Li Deng
J. Am. Chem. Soc. | 2012 | 10.1021/ja306771n

A new approach toward the asymmetric synthesis of optically active trifluoromethylated amines was enabled by an unprecedented, highly enantioselective catalytic isomerization of trifluoromethyl imines with a new chiral organic catalyst. Not only aryl but also...


Homocarbonates as Substrates for the Enantioselective Enzymatic Protection of Amines

Wilna Moree, Bernard Orsat, Phil B. Alper, Ching-Pong Mak, Chi-Huey Wong
J. Am. Chem. Soc. | 1996 | 10.1021/ja9533048



Carbonyl Allylation in the Absence of Preformed Allyl Metal Reagents:  Reverse Prenylation via Iridium-Catalyzed Hydrogenative Coupling of Dimethylallene

Eduardas Skucas, Michael J. Krische, John F. Bower
J. Am. Chem. Soc. | 2007 | 10.1021/ja075971u

Iridium-catalyzed hydrogenation of dimethylallene in the presence of aromatic, heteroaromatic, and aliphatic carbonyl electrophiles 1a−12a delivers products of reverse prenylation 1b−12b. Reductive coupling of dimethyl allene to aldehyde 8a under an...


Palladium-Catalyzed Intermolecular Dehydrogenative Aminohalogenation of Alkenes under Molecular Oxygen: An Approach to Brominated Enamines

Huanfeng Jiang, Xiaochen Ji, Wanqing Wu, Huawen Huang
J. Am. Chem. Soc. | 2013 | 10.1021/ja401034g

A novel and efficient palladium-catalyzed dehydrogenative aminohalogenation of alkenes with molecular oxygen as the sole oxidant has been developed. This protocol provides a valuable synthetic tool for the assembly of a wide range of brominated enamines under...

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