Formation and substitution of remote ester functionalized organocopper reagents
作者:Greg W. Ebert、James W. Cheasty、Safa S. Tehrani、Emmanuel Aouad
DOI:10.1021/om00040a028
日期:1992.4
Remote ester-functionalized aryl and alkyl organocopper compounds have been produced through the use of a highly reactive form of copper. Methyl 5-bromopentanoate and various alkyl halobenzoates undergo oxidative addition with active copper to produce methyl 5-cupriopentanoate and alkyl cupriobenzoates, respectively, in moderate to good yields. These organocopper reagents will cross-couple with acid chlorides to form the corresponding keto esters and with alkyl halides to produce the corresponding alkylated esters in moderate to good yields. The organocopper compounds could also be converted to their respective homocoupled dimers in varying yields by appropriate oxidative or thermal methods. Methyl 5-cupriopentanoate has a slight tendency to undergo an intramolecular cyclization to form, after aqueous workup, cyclopentanone and methanol.
Carbocupration/Zinc Carbenoid Homologation and β-Elimination Reactions for a New Synthesis of Allenes − Application to the Enantioselective Synthesis of Chiral Allenes by Deracemization of sp3-Organometallic Derivatives
作者:Jos P. Varghese、Irena Zouev、Lionel Aufauvre、Paul Knochel、Ilan Marek
straightforward carbocupration/zinc homologation/β-elimination reaction sequence allows the one-pot synthesis of polysubstituted allenes from acetylenic sulfoxides in excellent isolated chemical yields. Secondary zinccarbenoids were used for the homologation reaction, and so a new synthesis of 1,1-diiodoalkanes is described. This methodology also allows the synthesis of chiral allenes through thermodynamic
A Cobalt-Catalyzed Sulfonate/Copper Exchange for the Preparation of Highly Functionalized Electron-Deficient Aryl Copper Reagents
作者:Christoph J. Rohbogner、Coura R. Diène、Tobias J. Korn、Paul Knochel
DOI:10.1002/anie.200905379
日期:2010.3.1
Organocopper reagents from phenols: A new cobalt‐catalyzed arylsulfonate/copperexchange reaction allows the synthesis of highlyfunctionalizedarylcopperreagents from sulfonates bearing electron‐deficient substituents under mild conditions (25–45 °C, 1–6 h; see example). Sensitive functional groups, such as aldehydes, esters, and nitriles, are well‐tolerated.