Cyclopropanation of alkenes with metallocarbenes generated from monocarbonyl iodonium ylides
作者:Tristan Chidley、Graham K. Murphy
DOI:10.1039/c8ob02636j
日期:——
Reacting Wittigreagents and the hypervalent iodine reagent iodosotoluene, in the presence of 10 mol% Cu(tfacac)2 and 5 equiv. of alkene, results in a novel cyclopropanation reaction. The reagent combination is believed to generate a transient monocarbonyliodoniumylide (MCIY) in situ, which can be intercepted by the copper catalyst to give a metallocarbene. Both ester and ketone derived phosphoranes
Construction of Highly-Functionalized Cyclopentanes from Silyl Enol Ethers and Activated Cyclopropanes by [3+2] Cycloaddition Catalyzed by Triflic Imide
作者:Kiyosei Takasu、Satoshi Nagao、Masataka Ihara
DOI:10.1002/adsc.200600308
日期:2006.11
[3+2] Cycloadditions of silyl enol ethers with donor-acceptor (D-A) cyclopropanes, such as 2-alkoxycyclopropanecarboxylates and 2-(p-methoxyphenyl)cyclopropylphenylketone, proceed in the presence of a catalytic amount of triflic imide (Tf2NH) to give functionalized cyclopentanes in high yield. The catalytic process allows promotion of the cycloaddition of substrates incorporating Lewis basic functions
Asymmetric intermolecular cyclopropanation of alkenes by diazoketones catalyzed by Halterman iron porphyrins
作者:Irène Nicolas、Thierry Roisnel、Paul Le Maux、Gérard Simonneaux
DOI:10.1016/j.tetlet.2009.06.131
日期:2009.9
The asymmetric addition of diazoacetophenone to styrene derivatives to give optically active cyclopropyl ketones (ee up to 80%) was carried out rising chiral iron porphyrins as homogeneous catalysts. Intermolecular N-H functionalization of anilines by means of carbenoid-induced N-H insertion was also possible but without enantioselectivity. (C) 2009 Elsevier Ltd. All rights reserved.