136616-39-2Relevant academic research and scientific papers
Enantioselective synthesis of 1,2,3-trisubstituted cyclopropanes using gem-dizinc reagents
Zimmer, Lucie E.,Charette, Andre B.
scheme or table, p. 15624 - 15626 (2010/01/30)
(Chemical Equation Presented) The first asymmetric cyclopropanation of allylic alcohols using gem-dizinc carbenoids, which allows the synthesis of 1,2,3-substituted cyclopropane derivatives in high yields and excellent enantio- and diastereoselectivities,
Cyclopropanation of alkenes with CH2I2/Et3Al by the phase-vanishing method based on fluorous phase screen
Matsubara, Hiroshi,Tsukida, Masaaki,Yasuda, Shinji,Ryu, Ilhyong
scheme or table, p. 951 - 954 (2009/04/04)
Phase-vanishing (PV) method using perfluorohexanes as a screen phase was applied to cyclopropanation reactions with CH2I2/Et2Zn and CH2I2/Et3Al. When Et3Al was used as a carbenoid generator, the reaction proceeded smoothly and desired cyclopropane derivatives were obtained in high yield. The PV cyclopropanation took 2 or 3 days to complete, however, reduction of reaction time by a factor of 2-3 was also achieved by vigorous stirring after the bottom CH2I2 layer disappeared.
Stability, reactivity, solution, and solid-state structure of halomethylzinc alkoxides
Charette,Molinaro,Brochu
, p. 12160 - 12167 (2007/10/03)
In this paper, we report our findings regarding the development of a Lewis acid-catalyzed cyclopropanation of allylic alcohols with bis(iodomethyl)zinc. Iodomethylzinc alkoxides can be formed by treatment of an alcohol with bis(iodomethyl)zinc. These species are not prone to undergo cyclopropanation at low temperature but the addition of a Lewis acid in catalytic amounts induces the cyclopropanation reaction. Using this procedure, we demonstrated that the Lewis acid-catalyzed pathway significantly overwhelms the uncatalyzed one. This paper describes fundamental issues regarding the preparation and stability of halomethyl zinc alkoxides in solution as well as their aggregation state in solution and solid-state structures. Furthermore, the competition reaction between the inter- vs intramolecular cyclopropanation will be studied. Finally, we will discuss the possible activation pathways to explain the Lewis acid activation of halomethylzinc alkoxides. These findings provided new insights on the reactivity of ROZnCH2I and established the groundwork for the elaboration of an enantioselective version of the reaction.
New family of cyclopropanating reagents: Synthesis, reactivity, and stability studies of iodomethylzinc phenoxides
Charette, Andre B.,Francoeur, Sebastien,Martel, Jonathan,Wilb, Nicole
, p. 4539 - 4542 (2007/10/03)
A valuable alternative to the traditional Simmons-Smith reagents is offered by the title compounds, as a result of their ease of preparation and high reactivities towards unfunctionalized olefins (see scheme).
A Catalytic Enantioselective Reaction Using a C2-Symmetric Disulfonamide as a Chiral Ligand: Simmons-Smith Cyclopropanation of Allylic Alcohols by the Et2Zn-CH2I2-Disulfonamide System
Takahashi, Hideyo,Yoshioka, Masato,Shibasaki, Masakatsu,Ohno, Masaji,Imai, Nobuyuki,Kobayashi, Susumu
, p. 12013 - 12026 (2007/10/02)
A catalytic and enantioselective Simmons-Smith cyclopropanation of an allylic alcohol was developed by the reaction of an allylic alcohol with Et2Zn and CH2I2 in the presence of a catalytic amount of chiral disulfonamide 4.
A Comparison of (Chloromethyl)- and (Iodomethyl)zinc Cyclopropanation Reagents
Denmark, Scott E.,Edwards, James P.
, p. 6974 - 6981 (2007/10/02)
A study comparing the rate of cyclopropanation of a range of olefins using (chloromethyl)- and (iodomethyl)zinc reagents is described.The (chloromethyl)zinc reagent derived from diethylzinc and chloroiodomethane is generally more reactive than the (iodomethyl)zinc analogue.The use of 1,2-dichloroethane as the solvent for these reactions was shown to be a crucial factor necessary to achieve clean, rapid, high-yielding cyclopropanations.The well-known directing effect of proximal oxygen substituents on the stereochemical outcome of "Simmons-Smith" cyclopropanations was shown to hold for the (chloromethyl)zinc reagent as well.The diethylzinc/chloroiodomethane reagent system in 1,2-dichloroethane should prove to be a valuable alternative to traditional (iodomethyl)zinc-based cyclopropanation reagents.
