Ruthenium nanoparticles supported on non-cross-linked soluble polystyrene were prepared by reacting [RuCl
2
(C
6
H
5
CO
2
Et)]
2
with polystyrene in open air. They effectively catalyze intra- and intermolecular carbenoid insertion into C—H and N—H bonds, alkene cyclopropanation, and ammonium ylide/[2,3]-sigmatropic rearrangement reactions. This supported ruthenium catalyst is much more reactive than [RuCl
2
(p-cymene)]
2
and Ru(Por)CO] for catalytic intermolecular carbenoid C—H bond insertion into saturated alkanes. By using a-diazoacetamide as a substrate for intramolecular carbenoid C—H insertion, the supported ruthenium catalyst can be to recovered and reused for ten successive iterations without significant loss of activity.
Synthesis of chiral γ-lactams via Rh(II) catalyzed intramolecular C–H insertion: α-substituents and conformational effects
作者:David L. Flanigan、Cheol Hwan Yoon、Kyung Woon Jung
DOI:10.1016/j.tetlet.2004.10.159
日期:2005.1
γ-lactams are efficiently synthesized via Rh(II) catalyzed intramolecular C–H insertion from various α-diazoamides. Independent of α-substituents, regio- and stereoselectivities are enhanced through a conformational effect exerted by a bicyclictransitionstate.