845728-45-2

Upstream product

• 845728-44-1 N-formyl (4S,5S)-2,2-dimethyl-4-(4-(methylsulfonyl)phenyl)-5-amino-1,3-dioxane 
• 16854-32-3 (1S,2S)-(+)-thiomicamine 

Relevant academic research and scientific papers

Binaphthalene-derived iminium salt catalysts for highly enantioselective asymmetrie epoxidation

Enantiomerically enriched epoxides are useful intermediates that have found many applications in asymmetric synthesis, and development of efficient catalysts for asymmetric epoxidation has received considerable attention, In this manuscript we describe the design, preparation, and use of new highly selective imlnium salt organocatalysts for asymmetric epoxidation, based around a chiral binaphthalene motif coupled with a chiral substituted dioxane moiety. The new catalysts have been tested in the catalytic asymmetric epoxidation of unfunctionalized alkenes, and provide up to 95 % ee.

New chiral iminium salt catalysts for asymmetric epoxidation

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.

Asymmetric epoxidation of cis-alkenes mediated by iminium salts: Highly enantioselective synthesis of levcromakalim

(Chemical Equation Presented) A range of cis-substituted olefins has been epoxidized with a new dihydroisoquinolinium salt catalyst, using tetraphenylphosphonium monoperoxysulfate as the stoichiometric oxidant, giving ee's of up to 97%. The reaction has been used as the key step in an enantioselective synthesis of the antihypertensive agent levcromakalim.

PROCESS FOR USE IN THE PREPARATION OF OXIRANES FROM ALKENES, AND CATALYSTS FOR USE THEREIN

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.