Dearden MJ, McGrath MJ, O'Brien P. Evaluation of (+)-Sparteine-like Diamines for Asymmetric Synthesis.
J Org Chem 2004;
69:5789-92. [PMID:
15307761 DOI:
10.1021/jo049182w]
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Abstract
Three new (+)-sparteine-like diamines were prepared from (-)-cytisine and evaluated as sparteine surrogates in the alpha-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.
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