Abstract
An enantioselective Brønsted acid catalyzed Mannich reaction was developed for acetophenone derived enamines and N-Boc imines. An initial catalyst screen using 20 mol% (R,R)-TADDOL, (R)-BINOL, and (S)-H 8-BINOL, at -20°C in toluene, was performed to identify an appropriate Brønsted acid catalytic system for Mannich reaction of aryl methyl ketone with N-Boc aldamines. It was found that the absence of additives led to formation of only 10% of the product, as under the condition the background reaction was slow. The presence of (R,R)-TADDDOL increased the product formation to three times, but low levels of enantioselection were observed. It was also found that the acceleration was more significant in presence of (R)-BINOL. (S)-H2-BINOL was identified as the optimal catalyst to afford versatile β-amino aryl ketones in good yield and enantiomeric excess.
Original language | English |
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Pages (from-to) | 606-609 |
Number of pages | 3 |
Journal | Organic and Biomolecular Chemistry |
Volume | 5 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2007 |
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CCDC 626419: Experimental Crystal Structure Determination
Tillman, A. L. (Contributor) & Dixon, D. (Contributor), Cambridge Crystallographic Data Centre, 2006
DOI: 10.5517/ccp0v2l, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccp0v2l&sid=DataCite
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