Synthesis of Nitrogen-Containing Macrocycles with Reductive Intramolecular Coupling of Aromatic Diimines
摘要:
Reductive intramolecular coupling of aromatic diimines is an effective method for the synthesis of a variety of nitrogen-containing macrocycles. 1,4-Diazacrown ethers 3 were effectively synthesized by intramolecular coupling of bis(imino ethers) 9 promoted by electroreduction (method A) or chemical reduction with zinc powder (method B) in the presence of methanesulfonic acid. In spite of the formation of macrocycles, the yields of 3 were relatively high. This can be explained by the formation of proton-bridged intermediates 14, in which intramolecular hydrogen bonds are formed between hydrogen and oxygen atoms of diiminium salts. Method B was more effective in the formation of 1,4-diaza-12-crown-4 derivatives 3 (n = 1) due to the template effect of Zn2+. Optically active macrocyclic bislactones 4 were synthesized stereoselectively by reductive intramolecular coupling of bis(imino esters) 20 with zinc powder (method B). The high stereoselectivity is explained by considering proton-bridged intermediate 23. The resultant compounds 4 were transformed to optically active 1,2-diarylethylenediamines 7. Various sizes of macrocyclic bislactams 5 were synthesized by reductive intramolecular coupling of bis(imino amides) 26 with zinc powder (method B). Reduction of 5 gave the corresponding macrocyclic polyamines 6.
We herein report a general, practical, and highly efficient method for asymmetricsynthesis of a wide range of chiral vicinal diamines via reductive coupling of imines templated by chiral diboron. The protocol features high enantioselectivity and stereospecificity, mild reaction conditions, simple operating procedures, use of readily available starting materials, and a broad substrate scope. The method
Convenient routes to vicinal diamines. Coupling of nitriles or N-(trimethylsilyl) imines promoted by NbCl4(THF)2
作者:Eric J. Roskamp、Steven F. Pedersen
DOI:10.1021/ja00244a052
日期:1987.5
Reductive coupling of aromatic oxims and azines to 1,2-diamines using Zn-MsOH or Zn-TiCl 4
作者:Naoki Kise、Nasuo Ueda
DOI:10.1016/s0040-4039(01)00178-2
日期:2001.3
The reduction of aromatic aldoxims and azines with Zn in the presence of MsOH or TiCl4 afforded N.N'-unsubstituted 1,2-diamines in one-step. The reductive coupling with Zn-MsOH gave meso 1,2-diamines selectively, whereas cll 1,2-diamines were formed selectively by the reduction with Zn-TiCl4. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthesis of Nitrogen-Containing Macrocycles with Reductive Intramolecular Coupling of Aromatic Diimines
Reductive intramolecular coupling of aromatic diimines is an effective method for the synthesis of a variety of nitrogen-containing macrocycles. 1,4-Diazacrown ethers 3 were effectively synthesized by intramolecular coupling of bis(imino ethers) 9 promoted by electroreduction (method A) or chemical reduction with zinc powder (method B) in the presence of methanesulfonic acid. In spite of the formation of macrocycles, the yields of 3 were relatively high. This can be explained by the formation of proton-bridged intermediates 14, in which intramolecular hydrogen bonds are formed between hydrogen and oxygen atoms of diiminium salts. Method B was more effective in the formation of 1,4-diaza-12-crown-4 derivatives 3 (n = 1) due to the template effect of Zn2+. Optically active macrocyclic bislactones 4 were synthesized stereoselectively by reductive intramolecular coupling of bis(imino esters) 20 with zinc powder (method B). The high stereoselectivity is explained by considering proton-bridged intermediate 23. The resultant compounds 4 were transformed to optically active 1,2-diarylethylenediamines 7. Various sizes of macrocyclic bislactams 5 were synthesized by reductive intramolecular coupling of bis(imino amides) 26 with zinc powder (method B). Reduction of 5 gave the corresponding macrocyclic polyamines 6.