Abstract
A highly stereoselective methodology was developed to construct dihydrofurans. In the presence of a bifunctional squaramide catalyst, the Michael addition/cyclization between cyclohexane- 1,3-dione and α-bromonitroalkenes occurred smoothly to provide the desired dihydrofurans with high to excellent yields (90-94%) and good to high enantioselectivities (80-94% ee). This catalytic protocol was compatible with a range of structurally distinct α-bromonitroalkenes.
Keywords: Asymmetric catalysis, dihydrofuran, michael-alkylation reaction, tertiary amine-squaramide, organocatalysis, α-bromonitroalkene.
Graphical Abstract
[http://dx.doi.org/10.1039/a904850b] [PMID: 11152423]
[http://dx.doi.org/10.1021/jf010857v] [PMID: 11714332]
[http://dx.doi.org/10.1021/ol0169980] [PMID: 11796052]
[http://dx.doi.org/10.1021/jm020545z] [PMID: 14761182]
[http://dx.doi.org/10.1002/ejoc.200500489]
[http://dx.doi.org/10.1039/C6OB00593D] [PMID: 27108941]
[http://dx.doi.org/10.1016/S0065-2725(08)60594-2]
[http://dx.doi.org/10.1016/S0065-2725(08)60400-6]
[http://dx.doi.org/10.1021/cr940210s] [PMID: 11749289]
[http://dx.doi.org/10.1002/anie.201304107]
[http://dx.doi.org/10.1021/acs.orglett.8b03454] [PMID: 30540196]
[http://dx.doi.org/10.1021/acs.joc.9b01613] [PMID: 31362500]
[http://dx.doi.org/10.1021/acs.orglett.8b03612] [PMID: 30574783]
[http://dx.doi.org/10.1039/C9GC01751H]
[http://dx.doi.org/10.1021/jo101935k] [PMID: 21090776]
[http://dx.doi.org/10.1039/c2cc38534a] [PMID: 23318841]
[http://dx.doi.org/10.1021/ol102499r] [PMID: 21090798]
[http://dx.doi.org/10.1002/adsc.201401198]
[http://dx.doi.org/10.1002/ejoc.201800575]
[http://dx.doi.org/10.1039/C9CC01509D] [PMID: 31086904]
[http://dx.doi.org/10.1039/C9OB01974J] [PMID: 31803896]
[http://dx.doi.org/10.1021/acs.joc.0c00444] [PMID: 32830980]
[http://dx.doi.org/10.1039/D1QO00367D]
[http://dx.doi.org/10.1039/c0cs00200c] [PMID: 21399835]
[http://dx.doi.org/10.1021/ja805693p] [PMID: 18847268]
[http://dx.doi.org/10.1002/adsc.201401003]
[http://dx.doi.org/10.2174/1385272820666160805113749]
[http://dx.doi.org/10.3390/catal11050569]
[http://dx.doi.org/10.6023/cjoc201706025]
[http://dx.doi.org/10.1002/anie.200904779]