Lewis acid-promoted reactions of zirconacyclopentadienes with isocyanates. A one-pot three-component synthesis of multiply-substituted iminocyclopentadienes from one isocyanate and two alkynes
作者:Jiang Lu、Guoliang Mao、Wenxiong Zhang、Zhenfeng Xi
DOI:10.1039/b509142j
日期:——
Multiply-substituted iminocyclopentadienes were formed from Lewis acid-promoted reactions of zirconacyclopentadienes and isocyanates via a one-pot three-component coupling process; the C=O double bond of the RN=C=O moiety in the isocyanate was cleaved, and the isocyanates behaved formally as a one-carbon unit with Lewis acid-dependent and substituent-dependent reactions being realized.
多价取代的亚氨基环戊二烯是由路易斯酸促进的氧化锆环戊二烯与异氰酸酯的反应通过一锅三组分偶联过程形成的;异氰酸酯中的RN = C = O部分的C = O双键被裂解,并且异氰酸酯在形式上表现为单碳单元,实现了路易斯酸依赖性和取代基依赖性反应。
Reactions of 1,4-dilithiobutadienes with isothiocyanates: preparation of iminocyclopentadiene derivatives via cleavage of the CS double bond of a RNCS molecule
作者:Congyang Wang、Qiuling Song、Zhenfeng Xi
DOI:10.1016/j.tet.2004.04.045
日期:2004.6
Reaction patterns of 1,4-dilithio-butadiene derivatives with isothiocyanates RN=C=S and isocyanates RN=C=O were investigated and synthetically useful preparative methods were developed. Isothiocyanates reacted with 1,4-dilithio-butadienes to afford iminocyclopentadiene derivatives in excellent isolated yields and high selectivity. When aromatic isothiocyanates were used, cleavage of the C=S double bond of a RN C=S molecule took place via a successive inter-intramolecular carbophilic addition. A number of products were obtained from the reaction of isocyanates with 1,4-dilithio-butadienes, probably due to the high reactivity of isocyanates towards 1,4-dilithio-butadienes. (C) 2004 Elsevier Ltd. All rights reserved.
Lewis acid-controlled reactions of zirconacyclopentadienes with isocyanates and isothiocyanates. One-pot three- or four-component synthesis of multiply substituted iminocyclopentadienes and butadiene-tethered 1,6-bisamides and electrophilic cyclization
作者:Qiaoshu Hu、Jiang Lu、Congyang Wang、Chao Wang、Zhenfeng Xi
DOI:10.1016/j.tet.2007.02.015
日期:2007.7
products in high isolated yields from the reactions of zirconacyclopentadienes with isocyanates, depending on the substituents of isocyanates. The reactionpath and products could be controlled by Lewis acids. As a demonstration of the usefulness of thus obtained unsaturated bisamides, electrophilic cyclization using acids, NBS, and I2 was carried out. Electrophilic cyclization of multisubstituted conjugated