177600-48-5Relevant academic research and scientific papers
Evaluation of (+)-sparteine-like diamines for asymmetric synthesis
Dearden, Michael J.,McGrath, Matthew J.,O'Brien, Peter
, p. 5789 - 5792 (2004)
Three new (+)-sparteine-like diamines were prepared from (-)-cytisine and evaluated as sparteine surrogates in the α-lithiation rearrangement of cyclooctene oxide and the palladium(II)/diamine catalyzed oxidative kinetic resolution of 1-indanol. The new diamines exhibited opposite enantioselectivity to that observed with (-)-sparteine but increasing the steric hindrance of the N-alkyl group beyond N-Et had a detrimental effect on enantioselectivity. The optimal N-Me diamine was evaluated with much success in five other (-)-sparteine-mediated processes involving different metals (lithium, magnesium, and copper) and different types of reaction mechanisms.
α-Lithiation-rearrangement of N-toluenesulfonyl aziridines with sec-butyllithium and (-)-sparteine: Opposite sense of asymmetric induction to epoxides
O'Brien, Peter,Rosser, Clare M.,Caine, Darren
, p. 6613 - 6615 (2003)
The α-lithiation rearrangement of three cyclic N-toluenesulfonyl (tosyl) aziridines has been carried out using sec-butyllithium/(-)-sparteine. In each case, it was established that preferential lithiation of the S-aziridine stereocentre occurred. This is
On the α-lithiation-rearrangement of N-toluensulfonyl aziridines: Mechanistic and synthetic aspects
O'Brien, Peter,Rosser, Clare M.,Caine, Darren
, p. 9779 - 9791 (2007/10/03)
A detailed study of the rearrangement of five cycloalkene N-toluenesulfonyl (tosyl) aziridines using sec-butyllithium (with and without added ligands such as (-)-sparteine and TMEDA) has been carried out. Allylic sulfonamides were the main products from the cyclopentene and cyclohexene aziridines whereas bicyclic sulfonamides were obtained from the cycloheptene and cyclooctene aziridines. In most cases, p-toluenesulfonamide (TsNH 2) was produced as a by-product and a mechanistic explanation for its formation is forwarded. These reactions are believed to involve α-lithiation to a lithiated aziridine which can then partition through two pathways: (i) rearrangement to allylic or bicyclic sulfonamides via C-H insertion reactions or (ii) reductive alkylation to alkenes via attack by sec-butyllithium and subsequent elimination of TsNH2. In the (-)-sparteine reactions, the products were generated with 38-66% ee and the sense of asymmetric induction involved lithiation of the S-aziridine stereocentre. This is opposite to that observed with epoxides.
A readily-accessible (+)-sparteine surrogate
Dearden, Michael J.,Firkin, Catherine R.,Hermet, Jean-Paul R.,O'Brien, Peter
, p. 11870 - 11871 (2007/10/03)
A "(+)-sparteine-like" chiral diamine, readily synthesized in three steps from (-)-cytisine, has been evaluated in four different asymmetric transformations; in each case, selectivity in an enantiocomplementary fashion to (-)-sparteine was observed. Copyright
