| Abstract
| - Control of the conformational equilibria of 1,5-diaza-cis-decalins, a new class of chiral diamineligands, has been investigated. Chiral 2,6- and 3,7-substituted derivatives of 1,5-diaza-cis-decalinswere designed to stabilize the conformational form needed to chelate a lithium. These derivativeswere synthesized in optically pure form starting from 1,5-diaza-cis-decalin. Due to the rigid andconformationally well-defined nature of these compounds, the potential of these compounds as chiraldiamine ligands was investigated. Asymmetric lithiation−substitution reactions of N-Boc-pyrrolidineand N,N-diisopropyl-o-ethylbenzamide were performed using these ligands and up to 60% ee wasobtained. For the latter substrate, results spanning a range from 32% ee (R) to 60% ee (S) wereobtained (Δee = 92%) with 1,5-diaza-cis-decalin ligands differing only in the location of two methylsubstituents. Unlike many other diamines that have been employed in asymmetric lithiation−substitution reactions, the limited conformational flexibility of the 1,5-diaza-cis-decalins is analogousto (−)-sparteine such that these results may permit the construction of structure−activityrelationships.
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