facile synthesis of biologically important trans-functionalized cyclopentenes by a mild Rh(III)-catalyzed alkylation of strained diazabicyclic olefins with aryl ketones in the presence of ammonium acetate has been developed. The reaction proceeds through C–H bond activation of the aryl ketone groups by transforming them in to an autocleavable directing group, such as in situ-formed imine.
Rhodium(III)-catalyzed ring-opening of strained olefins through C–H activation of O-acetyl ketoximes: an efficient synthesis of trans-functionalized cyclopentenes and spiro[2.4]heptenes
作者:E. Jijy、Praveen Prakash、M. Shimi、S. Saranya、P. Preethanuj、Petri M. Pihko、Sunil Varughese、K.V. Radhakrishnan
DOI:10.1016/j.tetlet.2013.10.089
日期:2013.12
An efficient strategy for the stereoselectivesynthesis of functionalized cyclopentenes and spiro[2.4]heptenes from strained olefins via C–H activation of aryl ketone O-acetyl ketoximes using [RhCl2Cp∗]2 catalyst is described. The results revealed that a wide range of readily accessible aryl and heteroaryl ketoximes are compatible in this method for the ring opening of bicyclic and spirotricyclic olefins
Selective C-2 functionalization of N-protected and free indoles is reported. The ruthenium-catalyzed C-2 activation of indoles provided an easyaccess to cyclopentenylated indoles. Hydroheteroarylated bicyclic motifs were synthesized via iridium-catalyzed C-2 activation of NH indoles. The methodology was extended to different bicyclic adducts such as diaza- or urea-derived bicyclic olefins.
A Facile Access to trans-3-Styryl-4-hydrazinocyclopentenes via Palladium-Catalyzed Ring Opening of Diazanorbornenes with (Z)-β-Bromostyrenes/2,3-Dibromohydrocinnamic Acids
Abstract trans-3-Styryl-4-hydrazinocyclopentenes have been synthesized via palladium-catalyzed desymmetrization of diazanorbornenes with (Z)-β-bromostyrenes. The reaction also works well with (Z)-β-bromostyrenes generated in situ from 2,3-dibromohydrocinnamic acids. The synthesized hydrazinocyclopentenes provide an easy route towards synthetic intermediates of many scaffolds of biological potential
palladium-catalyzed [2+1] cycloaddition between ynamides and norbornenes or norbornadienes is reported. Both phosphapalladacycles and palladium/secondary phosphine oxide catalytic systems were found to be competent for the transformation allowing the preparation of aminomethylenecyclopropanes. The reaction showed general applicability to various functionalized bicyclo[2.2.1]hept-2-enes and ynamides. A chiral phosphapalladacycle