13854-07-4Relevant academic research and scientific papers
Chemo- and regioselective intermolecular cyclotrimerization of terminal alkynes catalyzed by cationic rhodium(I)/modified BINAP complexes: Application to one-step synthesis of paracyclophanes
Tanaka, Ken,Toyoda, Kazuki,Wada, Azosa,Shirasaka, Kaori,Hirano, Masao
, p. 1145 - 1156 (2005)
A highly regioselective intermolecular cyclotrimerization of terminal alkynes has been developed based on the use of the cationic rhodium(I)/DTBM- Segphos complex. This method can be applied to a variety of terminal alkynes to provide 1,2,4-trisubstituted benzenes in high yield and with high regioselectivity. A chemo- and regioselective intermolecular crossed-cyclotrimerization of dialkyl acetylenedicarboxylates with a variety of terminal alkynes has also been developed based on the use of the cationic rhodium(I)/H8-BINAP complex, furnishing 3,6-disubstituted phthalates in high yields. It constitutes a highly efficient new method for intermolecular crossed-cyclotrimerization of two different monoynes in terms of catalytic activity, chemo- and regioselectivity, scope of substrates, and ease of operation. The versatility of this new crossed-alkyne cyclotrimerization procedure is demonstrated through its application to one-step synthesis of a [6]metacyclophane and [7]-[12]paracyclophanes from the corresponding terminal α,ω-diynes. Mechanistic studies have revealed that the chemo- and regioselectivity of this crossed-alkyne cyclotrimerization are determined by the preferential formation of a specific rhodium metallacycle derived from a terminal alkyne and a dialkyl acetylenedicarboxylate.
Cyclotrimerization of terminal alkynes catalyzed by the system of NiCl 2/Zn and (benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines
Xi, Chanjuan,Sun, Zelin,Liu, Yongbing
supporting information, p. 13327 - 13330 (2013/09/23)
An effective regioselective cyclotrimerization of terminal alkynes is achieved by the direct utilization of NiCl2·6H2O, Zn, and 2-(benzimidazolyl)-6-(1-(arylimino)ethyl)pyridine in one step under ambient temperature.
Highly regioselective cyclotrimerization of terminal alkynes catalyzed by Fe(II) complexes bearing 2-(benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines
Liu, Yongbing,Yan, Xiaoyu,Yang, Nianfa,Xi, Chanjuan
experimental part, p. 489 - 492 (2011/12/15)
FeCl2 ligated with 2-(benzimidazolyl)-6-(1-(arylimino)ethyl) pyridine in the presence of zinc powder and zinc iodide could effectively catalyze cyclotrimerization of intermolecular alkynes to afford benzene derivatives in high regioselectivity. The synthetic usefulness of this catalytic system consisting of Fe(II) complex C1, Zn and ZnI2 in acetonitrile was tested with various terminal alkynes. In the cases of using aryl substituted alkynes, the 1,2,4-trisubstituted benzenes 2 were found to be the major products.
The first cobalt catalyzed [2 + 2 + 2] alkyne cyclotrimerization in aqueous medium at room temperature
Yong, Li,Butenschoen, Holger
, p. 2852 - 2853 (2007/10/03)
Chelate complex 1 (5 mol%) was found to catalyze the [2 + 2 + 2] cyclization of terminal alkynes in good yields in a 80/20 mixture of water and ethanol at room temperature without further activation.
