Enantioselective Ni–Al Bimetallic Catalyzed exo-Selective C–H Cyclization of Imidazoles with Alkenes
摘要:
A Ni-Al bimetallic catalyzed enantioselective C-H exo-selective cyclization of imidazoles with alkenes has been developed. A series of bi- or polycyclic imidazoles with beta-stereocenter were obtained in up to 98% yield and >99% ee. The bifunctional SPO ligand-promoted bimetallic catalysis proved to be critical to this challenging stereocontrol.
A pharmaceutical composition having as an essential ingredient a compound of the formula ##STR1## wherein one to three of R.sup.1, R.sup.2 and R.sup.3 represent an alkenyl group having from 4 to 8 carbon atoms, the other ones are alkyl having from 1 to 12 carbon atoms, and R.sup.1 may also be hydrogen, the compounds themselves and a process for preparing them.
comprehensive liquid operating temperature range (−70 to 215 °C), and a high density-specific impulse (342.2 s·g·cm−3). This study is expected to pave the way for developing bio-renewable hypergolic ILs from natural sources.