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Catalytic Asymmetric Hydrogenation: Toward Chiral Diamines and Cyclohexanes

Posted on:2012-06-28Degree:M.ScType:Thesis
University:University of Toronto (Canada)Candidate:Pignatelli, JosephFull Text:PDF
GTID:2451390011950281Subject:Chemistry
Abstract/Summary:
As the need for developing environmentally friendly chemistry continues to become more apparent, catalytic asymmetric hydrogenation has risen to the forefront as a reliable and eco-friendly method for enantioselective synthesis. We herein describe our progress toward the synthesis of valuable structural motifs via hydrogenation: chiral 1,2-diamines, 1,3-diamines and substituted cyclohexanes.;We propose a strategy whereby protected 1,2-diimine and 1,3-diimine surrogates can be hydrogenated selectively and deprotected to furnish the desired chiral amines. Using this strategy, it was demonstrated that imidazolone precursors could be hydrogenated with >20:1 diastereoselectivity to give latent 1,2-diamines, albeit with no enantiomeric excess.;We further propose that substituted benzene rings linked to an oxazolidinone chiral-auxiliary can be diastereoselectively hydrogenated using a heterogeneous metal catalyst. Following hydrogenation, the chiral cyclohexanes could be obtained in up to quantitative yield and 99% diastereomeric excess.
Keywords/Search Tags:Hydrogenation, Chiral
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