81639-93-2Relevant academic research and scientific papers
Amide-Group-Directed Protonolysis of Cyclopropane: An Approach to 2,2-Disubstituted Pyrrolidines
Skvorcova, Marija,Jirgensons, Aigars
, p. 2478 - 2481 (2017/05/24)
Regioselective protonolytic C-C bond cleavage of acylated aminomethyl cyclopropanes can be achieved using trifluoroacetic acid. The intermediate tertiary carbenium ion undergoes an intramolecular amination to give 2,2-substituted pyrrolidines. The strength of the acid and the amine substituent are important factors to achieve high regioselectivity, suggesting intramolecular proton transfer from the protonated amide function. Preliminary mechanistic studies revealed that cyclopropane cleavage proceeds with retention of configuration at the carbon to which the proton is attached. This observation is consistent with the "edge" protonation trajectory of the C-C bond.
Highly asymmetric intramolecular cyclopropanation of acceptor-substituted diazoacetates by Co(II)-based metalloradical catalysis: Iterative approach for development of new-generation catalysts
Xu, Xue,Lu, Hongjian,Ruppel, Joshua V.,Cui, Xin,Lopez De Mesa, Silke,Wojtas, Lukasz,Zhang, X. Peter
, p. 15292 - 15295 (2011/11/04)
3,5-DitBu-QingPhyrin, a new D2-symmetric chiral porphyrin derived from a chiral cyclopropanecarboxamide containing two contiguous stereocenters, has been developed using an iterative approach based on Co(II)-catalyzed asymmetric cyclopropanation of alkenes. The Co(II) complex of 3,5-DitBu-QingPhyrin, [Co(P2)], has proved to be a general and effective catalyst for asymmetric intramolecular cyclopropanation of various allylic diazoacetates (especially including those with α-acceptor substituents) in high yields with excellent stereoselectivities. The [Co(P2)]-based intramolecular metalloradical cyclopropanation provides convenient access to densely functionalized 3-oxabicyclo[3.1.0]hexan-2-one derivatives bearing three contiguous quaternary and tertiary chiral centers with high enantiomeric purity.
The Photochemistry of 1-Cyano-2-methyl-3-phenylpropene and Ring substituted Derivatives
Ferreira, Aurelio B. B.,Salisbury, Kingsley
, p. 25 - 30 (2007/10/02)
The E- and Z-isomers of 1-cyano-2-methyl-3-phenylpropene and ring-substituted derivatives of the E-isomer, are shown to fluoresce and undergo Z-E-isomerization and di-?-methane rearrangement on irradiation.The rate constants for these processes, obtained from fluorescence lifetimes and quantum yields, can be analysed in terms of an initial interaction between the two ? systems, facilitated by partial charge-transfer, followed by two diverging pathways, one, towards a diradicaloid species leading to cyclopropane formation, the other towards a 'zwitterionic' species and relaxation to the ground state and resulting in singlet state Z-E-isommerization.
