760976-21-4Relevant academic research and scientific papers
Highly enantioselective desymmetrization of anhydrides by carbon nucleophiles: Reactions of Grignard reagents in the presence of (-)-sparteine
Shintani, Ryo,Fu, Gregory C.
, p. 1057 - 1059 (2002)
Where other common chiral ligands failed, (-)-sparteine can be employed to form complexes with Grignard reagents. These chirally modified reagents desymmetrize a range of anhydrides with good enantioselectivity (up to 92% ee; see scheme). Whereas (-)-sparteine is well known to form complexes with organolithium reagents and to induce excellent enantioselection in their reactions with electrophiles, (-)-sparteine-controlled asymmetric processes that involve Grignard reagents are rare.
Ligand differentiated complementary Rh-catalyst systems for the enantioselective desymmetrization of meso-cyclic anhydrides
Johnson, Jeffrey B.,Cook, Matthew J.,Rovis, Tomislav
supporting information; experimental part, p. 3202 - 3210 (2009/08/15)
Two distinct systems for the rhodium-catalyzed enantioselective desymmetrization of meso-cyclic anhydrides have been developed. Each system has been optimized and are compatible with the use of in situ prepared organozinc reagents. Rhodium/PHOX species efficiently catalyze the addition of alkyl nucleophiles to glutaric anhydrides, while a rhodium/phosphoramidite system is effective in the enantioselective arylation of succinic and glutaric anhydrides.
Evaluation of (+)-sparteine-like diamines for asymmetric synthesis
Dearden, Michael J.,McGrath, Matthew J.,O'Brien, Peter
, p. 5789 - 5792 (2007/10/03)
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.
