720712-04-9Relevant academic research and scientific papers
Light-induced enantiospecific 4π ring closure of axially chiral 2-pyridones: Enthalpic and entropic effects promoted by H-bonding
Kumarasamy, Elango,Jesuraj, Josepha L.,Omlid, Joseph N.,Ugrinov, Angel,Sivaguru, Jayaraman
, p. 17106 - 17109 (2011/12/13)
Nonbiaryl axially chiral 2-pyridones were synthesized and employed for light-induced electrocyclic 4π ring closure leading to bicyclo-β-lactam photoproducts in solution. The enantioselectivity in the photoproducts varied from 22 to 95% depending on the reaction temperature and the ability of the axially chiral chromophore to form intramolecular and/or intermolecular H-bonds with the solvent. On the basis of the differential activation parameters, entropic control of the enantiospecificity was observed for 2-pyridones lacking the ability to form H-bonds. Conversely, enthalpy played a significant role for 2-pyridones having the ability to form H-bonds.
Synthesis of 2-azabicyclo[4.1.0]heptanes through stereoselective cyclopropanation reactions
Suarez Del Villar, Irene,Gradillas, Ana,Perez-Castells, Javier
experimental part, p. 5850 - 5862 (2011/03/17)
Unsaturated δ-lactams are cyclopropanated with the aid of diazo compound decomposition catalysed by metal complexes. A study of the reaction conditions, stereochemical outcome and group protection is reported. The resulting bicyclic products are related to bioactive compounds. Transformation into thiolactams facilitates the separation of the different isomers obtained and the removal of the protecting group. The cyclopropanation reaction works with diverse diazo compounds. Unsaturated δ-lactams are cyclopropanated with the aid of diazo compound decomposition catalysed by metal complexes. A study of the reaction conditions, stereochemical outcome and group protection isreported. Transformation into thiolactams assists in separation of the different isomers obtained and removal of the protecting group.
Stereoselectivity in reactions of atropisomeric lactams and imides
Bennett, D. Jonathan,Blake, Alexander J.,Cooke, Paul A.,Godfrey, Christopher R.A.,Pickering, Paula L.,Simpkins, Nigel S.,Walker, Matthew D.,Wilson, Claire
, p. 4491 - 4511 (2007/10/03)
A range of reactions of cyclic lactam systems is described in which an atropisomeric C-N axis controls the stereochemical outcome of ring substitution or addition. In the case of enantiopure menthol adducts, substitution via N-acyliminium intermediates occurred with essentially complete control. However, the range of nucleophiles that participate in the reaction is very limited and at present the removal of the N-aryl substituent is problematic. A six-membered enamide is of moderate configurational stability and the axis exerts synthetically useful levels of control over enolate alkylations of the system. A novel Lewis acid mediated enamide arylation process was identified.
A convenient synthesis of hindered N-ARYL substituted cyclic amines
Akula, Murthy R.,Kabalka, George W.
, p. 2063 - 2070 (2007/10/03)
An efficient and high yielding synthesis of N-substituted pyrrolidines and piperidines is described.
