450412-22-3Relevant academic research and scientific papers
Combined directed ortho-zincation and palladiumcatalyzed strategies: Synthesis of 4,n-dimethoxysubstituted benzo[b]furans
Guilarte, Veronica,Castroviejo, M. Pilar,Alvarez, Estela,Sanz, Roberto
supporting information; experimental part, p. 1255 - 1260 (2011/10/30)
A new route to regioselectively dialkoxy-functionalized benzo[b]furan derivatives has been developed from 3-halo-2-iodoanisoles bearing an additional methoxy group, which have been accessed through an ortho-zincation/iodination reaction. Two palladiumcata
Approaches to the synthesis of 2,3-dihaloanilines. Useful precursors of 4-functionalized-1 H-indoles
Guilarte, Veronica,Castroviejo, M. Pilar,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Sanz, Roberto
scheme or table, p. 3416 - 3437 (2011/06/28)
2,3-Dihaloanilines have been proved as useful starting materials for synthesizing 4-halo-1H-indoles. Subsequent or in situ functionalization of the prepared haloindoles allows the access to a wide variety of 2,4- or 2,3,4-regioselectively functionalized indoles in good overall yields. As no efficient synthetic routes to 2,3-dihaloanilines have been described in the literature, different approaches to the preparation of these 1,2,3-functionalized aromatic precursors are now presented. The most general one involves a Smiles rearrangement from the corresponding 2,3-dihalophenols and allows the preparation of 2,3-dihaloanilides in a straightforward and synthetically useful manner.
Synthesis of 4-functionalized-1H-indoles from 2,3-dihalophenols
Sanz, Roberto,Guilarte, Veronica,Garcia, Nuria
supporting information; experimental part, p. 3860 - 3864 (2010/09/17)
A new synthesis of 4-halo-1H-indoles has been developed from easily available 2,3-dihalophenol derivatives. The key steps are Smiles rearrangement and a one-pot or stepwise Sonogashira coupling/NaOH-mediated cyclization. Subsequent functionalization allows access to a wide variety of 2,4- or 2,3,4-regioselectively functionalized indoles.
Generation and suppression of 3-/4-functionalized benzynes using zinc ate base (TMP-Zn-ate): New approaches to multisubstituted benzenes
Uchiyama, Masanobu,Kobayashi, Yuri,Furuyama, Taniyuki,Nakamura, Shinji,Kajihara, Yumiko,Miyoshi, Tomoko,Sakamoto, Takao,Kondo, Yoshinori,Morokuma, Keiji
, p. 472 - 480 (2008/10/09)
We present full details of our new methods for preparing functionalized benzynes with lithium di-alkyl(2,2,6,6-tetramethylpiperidino)zincate (R 2Zn(TMP)Li) through deprotonative zincation as a key reaction. In this system, by choosing appropriate ligands for the zincate, either regioselective zincation of functionalized haloaromatics or the generation of substituted benzynes can be controlled in good yields with excellent chemoselectivity, using the same substrate. Zincation with tBu 2Zn(TMP)Li followed by electrophilic trapping or zincation with Me2Zn(TMP)Li followed by nucleophilic or diene trapping is shown to be a powerful tool for the chemoselective preparation of 1,2,3-/1,2,4- trisubstituted benzene derivatives. These methods offer far greater generality than previous methods for the synthesis of multifunctionalized benzenes. Computational/theoretical studies of the reaction mechanism of this unique benzyne formation indicated that preferential coordination of the dialkylzinc moiety of zincate to halogen is the reason for the reduced activation energy of the elimination, that is, for the formation of the benzyne. The role of the ligands on Zn in accelerating/decelerating the elimination is also discussed.
Regioselective synthesis of 4- and 7-alkoxyindoles from 2,3-dihalophenols: Application to the preparation of indole inhibitors of phospholipase A 2
Sanz, Roberto,Castroviejo, M. Pilar,Guilarte, Veronica,Perez, Antonio,Fananas, Francisco J.
, p. 5113 - 5118 (2008/02/05)
(Chemical Equation Presented) An efficient and regioselective synthesis of 4- and 7-alkoxyindoles has been developed from commercially available starting materials such as 3-halophenols and 3-chloroanisole. Directed ortho-metalation followed by two pallad
Generation of functionalized asymmetric benzynes with TMP-zincates. Effects of ligands on selectivity and reactivity of zincates
Uchiyama, Masanobu,Miyoshi, Tomoko,Kajihara, Yumiko,Sakamoto, Takao,Otani, Yuko,Ohwada, Tomohiko,Kondo, Yoshinori
, p. 8514 - 8515 (2007/10/03)
We have developed new methods for preparing functionalized benzynes through deprotonative zincation as a key reaction using R2Zn(TMP)Li, and we also describes dramatic ligand effects on the benzyne formation. Deprotonative zincation of various meta-substituted bromobenzenes with Me2Zn(TMP)Li proved effective for the one-pot generation of various 3-functionalized benzynes, particularly those electrophilic substituents such as ester, amide, and cyano. On the other hand, zincation with tBu2Zn(TMP)Li, followed by electrophilic trapping (with I2) proved a powerful tool for the preparation of 1,2,3-trisubstituted aromatic compounds.8 The resultant 1,2,3-trisubstituted benzenes are available as precursors for generation of 3-substituted benzynes by halogen-zinc exchange reactions with Me3ZnLi. These methods offer far greater generality than previous methods for the synthesis of functionalized asymmetric benzynes, and should be of value in new syntheses of various natural products and functional materials. In addition, these results underline the utility of spectator ligands on the central metal of ate complexes as a tunable functionality in the development of new ate complex-promoted reactions. Copyright
