1227296-89-0Relevant academic research and scientific papers
Silyl fluoride electrophiles for the enantioselective synthesis of silylated pyrrolidine catalysts
Jentzsch, Kaleb I.,Min, Taewoo,Etcheson, Jennifer I.,Fettinger, James C.,Franz, Annaliese K.
, p. 7065 - 7075 (2011)
Chiral silylated pyrrolidine catalysts are obtained in high yield and enantioselectivity by sparteine-mediated lithiation of N-Boc-py rolidine and addition to silyl fluoride electrophiles. The activity and enantioselectivity of a new tert-butyldiphenylsilylpyrrolidine catalyst has been demonstrated for various asymmetric Michael reactions at 5 mol% catalyst loading and affords up to 99% ee for asymmetric Michael reactions with aldehydes and nitro-olefins. Acetaldehyde donors proceed with yields up to 77% and enantioselectivities up to 96% ee, avoiding common side reactions that often lower yields. Insight into the mechanism of pyrrolidine-based catalysts is provided by demonstrating ESI mass spectrometry evidence for activation of a nitro acceptor by formation of a hydrogen-bonding adduct with the catalyst amine. Analysis of reaction intermediates using mass spectrometry provides evidence that the pyrrolidine catalyst also plays a role in activating nitro-olefins through hydrogen-bonding.
Silyl-modified analogues of 2-tritylpyrrolidine: Synthesis and applications in asymmetric organocatalysis
Bauer, Jonathan O.,Stiller, Julian,Marques-Lopez, Eugenia,Strohfeldt, Katja,Christmann, Mathias,Strohmann, Carsten
supporting information; experimental part, p. 12553 - 12558 (2011/02/21)
Silicon-based organocatalysts: In an effort to study the effects of substituting carbon by silicon within the catalyst backbone, we developed an efficient synthesis of (S)-2-triphenylsilylpyrrolidine [(S)-2]. The evaluation of (S)-2 against its carbon analogue (S)-1 in two organocatalytic reactions is complemented by computational studies.
