5009-15-4Relevant academic research and scientific papers
Carbonylative C?C Bond Activation of Electron-Poor Cyclopropanes: Rhodium-Catalyzed (3+1+2) Cycloadditions of Cyclopropylamides
Dalling, Andrew G.,Yamauchi, Takayuki,McCreanor, Niall G.,Cox, Lydia,Bower, John F.
, p. 221 - 225 (2018/12/11)
Rh-catalyzed carbonylative C?C bond activation of cyclopropylamides generates configurationally stable rhodacyclopentanones that engage tethered alkenes in (3+1+2) cycloadditions. These studies provide the first examples of multicomponent cycloadditions t
Modular Access to Substituted Azocanes via a Rhodium-Catalyzed Cycloaddition-Fragmentation Strategy
Shaw, Megan H.,Croft, Rosemary A.,Whittingham, William G.,Bower, John F.
, p. 8054 - 8057 (2015/07/15)
A short entry to substituted azocanes by a Rh-catalyzed cycloaddition-fragmentation process is described. Specifically, exposure of diverse N-cyclopropylacrylamides to phosphine-ligated cationic Rh(I) catalyst systems under a CO atmosphere enables the directed generation of rhodacyclopentanone intermediates. Subsequent insertion of the alkene component is followed by fragmentation to give the heterocyclic target. Stereochemical studies show, for the first time, that alkene insertion into rhodacyclopentanones can be reversible.
Reversible C-C bond activation enables stereocontrol in Rh-catalyzed carbonylative cycloadditions of aminocyclopropanes
Shaw, Megan H.,McCreanor, Niall G.,Whittingham, William G.,Bower, John F.
supporting information, p. 463 - 468 (2015/01/30)
Upon exposure to neutral or cationic Rh(I)-catalyst systems, amino-substituted cyclopropanes undergo carbonylative cycloaddition with tethered alkenes to provide stereochemically complex N-heterocyclic scaffolds. These processes rely upon the generation and trapping of rhodacyclopentanone intermediates, which arise by regioselective, Cbz-directed insertion of Rh and CO into one of the two proximal aminocyclopropane C-C bonds. For cyclizations using cationic Rh(I)-systems, synthetic and mechanistic studies indicate that rhodacyclopentanone formation is reversible and that the alkene insertion step determines product diastereoselectivity. This regime facilitates high levels of stereocontrol with respect to substituents on the alkene tether. The option of generating rhodacyclopentanones dynamically provides a new facet to a growing area of catalysis and may find use as a (stereo)control strategy in other processes.
Directing group enhanced carbonylative ring expansions of amino-substituted cyclopropanes: Rhodium-catalyzed multicomponent synthesis of N-heterobicyclic enones
Shaw, Megan H.,Melikhova, Ekaterina Y.,Kloer, Daniel P.,Whittingham, William G.,Bower, John F.
supporting information, p. 4992 - 4995 (2013/05/22)
Aminocyclopropanes equipped with suitable N-directing groups undergo efficient and regioselective Rh-catalyzed carbonylative C-C bond activation. Trapping of the resultant metallacycles with tethered alkynes provides an atom-economic entry to diverse N-heterobicyclic enones. These studies provide a blueprint for myriad N-heterocyclic methodologies.
