50731-62-9Relevant academic research and scientific papers
New chiral iminium salt catalysts for asymmetric epoxidation
Bulman Page, Philip C.,Buckley, Benjamin R.,Rassias, Gerasimos A.,Blacker, A. John
, p. 803 - 813 (2007/10/03)
A range of enantiomerically pure 4-substituted 5-amino-1,3-dioxanes has been condensed with 2-(2-bromoethyl)benzaldehyde to produce chiral dihydroisoquinolinium salts, which are effective asymmetric catalysts for the epoxidation of simple alkenes, giving ees of up to 71 %. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
PROCESS FOR USE IN THE PREPARATION OF OXIRANES FROM ALKENES, AND CATALYSTS FOR USE THEREIN
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Page/Page column 10, (2010/02/12)
There is provided a process for the preparation of oxiranes wherein an optionally substituted alkene is reacted in the presence of a chiral catalyst, an oxidant and an organic solvent characterised in that the oxidant is at least partially soluble in the organic solvent and the oxidant displays low reactivity towards the alkene in the absence of the catalyst. The optionally substituted alkene is preferably an alkene of formula (1): wherein: R1-4 each independently are hydrogen, an optionally substituted aromatic or is saturated hydrocarbyl, an optionally substituted hetrocyclyl, an optionally substituted aromatic or saturated hydrocarbyloxy, an optionally substituted aromatic or saturated hydrocarbylamino, an optionally substituted aromatic or saturated hydrocarbyloxycarbonyl, an optionally substituted aromatic or saturated hydrocarbylaminocarbonyl, nitrile, halide or one or more of R1& R2, R2& R3 , R3& R4 , R1& R4 optionally being linked in such a way as to form an optionally substituted ring(s). The oxidant is preferably an oxidant of formula (2): A+ HSO5- wherein A+ is a counterion capable of conferring organic solvent solubility. Preferred chiral catalysts of formula (4): wherein: R11 and R12 are each independently an optionally substituted hydrocarbyl group or R11& R12 are linked in such a way as to form an optionally substituted ring(s); R13 is hydrogen or an optionally substituted hydrocarbyl group; R14 is an optionally substituted hydrocarbyl group; R17 is hydrogen or an optionally substituted hydrocarbyl group; R15 and R16 each independently are hydrogen or an optionally substituted hydrocarbyl group; and 30 X- is a counterion; * is a chiral centre; and *' is a chiral centre when R17 is not hydrogen are provided.
A NEW ENTRY TO THE SYNTHESIS OF β-HYDROXYTYROSINES VIA A NOVEL BENZYLIC HYDROXYLATION
Shimamoto, Keiko,Ohfune, Yasufumi
, p. 5177 - 5180 (2007/10/02)
Highly stereoselective introduction of a hydroxyl group into the benzylic position of N-tert-butoxycarbonyl-L-tyrosine derivatives was achieved by the use of K2S2O8/CuSO4 system to give the threo cyclic carbamates.These were converted into β-hydroxytyrosine and octopamine, efficiently.
