C−H Carbene Insertion of α-Diazo Acetamides by Photolysis in Non-Conventional Media
摘要:
Light from a mercury vapor high-pressure lamp was used to induce the photolytic decomposition of alpha-diazo acetamides in hexane and in nonconventional media such as water or a film. The corresponding beta- and/or gamma-lactams were obtained in reasonable yields and in some cases with good diastereoselectivities with no need to use a metallic catalyst. Experimental studies on chiral substrates demonstrated the occurrence of insertion with retention of configuration.
Rh(II)-Catalyzed Intramolecular C−H Insertion of Diazo Substrates in Water: Scope and Limitations
摘要:
Preferential Rh(II) carbenoid intramolecular C-H versus O-H insertion derived from R-diazo-acetamides can be achieved in water by using an appropriate combination of the catalyst and amide groups, which creates a larger hydrophobic environment around the reactive carbenoid center.
Rh(<scp>ii</scp>) catalysed intramolecular C–H insertion of diazo substrates in water: a simple and efficient approach to catalyst reuse
作者:Nuno R. Candeias、Pedro M. P. Gois、Carlos A. M. Afonso
DOI:10.1039/b414233k
日期:——
Water is an efficient solvent for the Rh2(OAc)4 catalysedintramolecular C-H insertion of a range of diazo substrates without competitive water insertion. Due to the high solubility and stability of the catalyst in water, the catalyst can be efficiently reused.
Intramolecular C–H insertion using NHC–di-rhodium(II) complexes: the influence of axial coordination
作者:Luis F.R. Gomes、Alexandre F. Trindade、Nuno R. Candeias、Pedro M.P. Gois、Carlos A.M. Afonso
DOI:10.1016/j.tetlet.2008.10.054
日期:2008.12
insertion of diazo-acetamides catalysed by di-rhodium(II) complexes can be highly influenced by the axial ligand on the di-rhodium(II) complex. Axially monocoordinated NHC–Rh2(OAc)4 complexes have a distinct reactivity from the parent Rh2(OAc)4 complex affording the cyclisation products in different rates and selectivities. Surprisingly, a new reaction mode emerged when using these complexes which led