“Widening the Roof”:  Synthesis and Characterization of New Chiral C 1-Symmetric Octahydrofluorenyl Organolanthanide Catalysts and Their Implementation in the Stereoselective Cyclizations of Aminoalkenes and Phosphinoalkenes

New chiral C 1-symmetric organolanthanide catalysts of the type Me2Si(OHF)(CpR*)LnN(TMS)2 (OHF = η5-octahydrofluorenyl; Cp = η5-C5H3; R* = (−)-menthyl; Ln = Sm, Y, Lu; TMS = SiMe3) have been synthesized, characterized, and implemented in the enantioselective and diastereoselective cyclizations of am...

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Bibliographic Details
Published in:Organometallics 2002-01, Vol.21 (2), p.283-292
Main Authors: Douglass, Michael R, Ogasawara, Masamichi, Hong, Sukwon, Metz, Matthew V, Marks, Tobin J
Format: Article
Language:English
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Summary:New chiral C 1-symmetric organolanthanide catalysts of the type Me2Si(OHF)(CpR*)LnN(TMS)2 (OHF = η5-octahydrofluorenyl; Cp = η5-C5H3; R* = (−)-menthyl; Ln = Sm, Y, Lu; TMS = SiMe3) have been synthesized, characterized, and implemented in the enantioselective and diastereoselective cyclizations of aminoalkenes and phosphinoalkenes. Me2Si(OHF)(CpR*)LnCl2 -Li(DME)2 + catalyst precursors can be prepared in up to ∼90% diastereomeric purity and then converted into the corresponding amido catalysts, which can be isolated in ∼100% diastereomeric purity after recrystallization. The catalyst (S)-Me2Si(OHF)(CpR*)YN(TMS)2 has been crystallographically characterized. The activity of these catalysts for the hydroamination/cyclization of aminoalkenes and for the hydrophosphination/cyclization of phosphinoalkenes is described. Enantioselectivites as high as 67% are obtained in hydroamination, and diastereoselectivities of as high as 96% are obtained in hydrophosphination.
ISSN:0276-7333
1520-6041
DOI:10.1021/om0104013