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The barrier to enantiomerization of N-Boc-2-lithiopyrrolidine: the effect of chiral and achiral diamines.

ABSTRACT: (-)-Sparteine and TMEDA dramatically lower both enthalpy and entropy of activation for the barrier to enantiomerization of N-Boc-2-lithiopyrrolidine in diethyl ether, whereas N,N'-diisopropylbispidine has little effect; the entropy of activation for enantiomerization is zero in the presence of TMEDA and slightly negative in the presence of sparteine; these data suggest a subtle change in mechanism of enantiomerization in the presence of TMEDA and sparteine.

SUBMITTER: Yousaf TI

PROVIDER: S-EPMC2607545 | biostudies-literature | 2008 Jan

REPOSITORIES: biostudies-literature

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The barrier to enantiomerization of N-Boc-2-lithiopyrrolidine: the effect of chiral and achiral diamines.

Yousaf Taher I TI Williams Roger L RL Coldham Iain I Gawley Robert E RE

Chemical communications (Cambridge, England) 20080101 1

(-)-Sparteine and TMEDA dramatically lower both enthalpy and entropy of activation for the barrier to enantiomerization of N-Boc-2-lithiopyrrolidine in diethyl ether, whereas N,N'-diisopropylbispidine has little effect; the entropy of activation for enantiomerization is zero in the presence of TMEDA and slightly negative in the presence of sparteine; these data suggest a subtle change in mechanism of enantiomerization in the presence of TMEDA and sparteine. ...[more]

PMID: 18399412

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