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.
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.