Generation of homochiral aziridinium ion intermediates derived from 2,3-epoxy amines: regiospecific nucleophilic trapping with nitrogen nucleophiles. Application in the synthesis of novel morpholinosphingolipid analogues with potential glucosylceramide synthase inhibitory activity

Abstract

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Dynamic Biphasic Counterion Exchange in a Configurationally Stable Aziridinium Ion: Efficient Synthesis and Isolation of a Koga C2-Symmetric Tetraamine Base

“…Further insight into the mechanism and driving force for the counterion exchange was gained by evaluating the solubilities of the reacting partners in the MTBE phase. As can be seen from Table , these studies revealed that, while β-chloroamine 12 was soluble in MTBE to 115 mg/mL, aziridinium mesylate 10a was only soluble to 5 mg/mL and Et 3 N·HCl was soluble to less than 0.1 mg/mL. These data point to a biphasic process wherein counterion exchange occurs upon precipitation of 10a and β-chloroamine 12 is re-extracted into the MTBE phase (Scheme ).…”

The aza-Payne rearrangement: a synthetically valuable equilibration

“…The direction of the equilibrium of the aza-Payne rearrangement of epoxy amines has been investigated by many research groups. [9][10][11][12][13][14][15][16][17]19 It is well established by Rayner [9][10][11] that quantitative generation of quaternary aziridinium salt 98 could be accomplished by exposure of 2,3-epoxy N,N-diallylamine 97 to trimethysilyl triflate (Scheme 16); a process that is essentially irreversible. However, desilylation of the aziridinium salt 98 by treatment with potassium carbonate in methanol regenerates the original 2,3-epoxy diallylamine 97 and it would appear that, at least in this present case, desilylation and subsequent aziridinium ion ring-opening to yield original 2,3-epoxy amine 97 is a more favourable process.…”

“…8 Recently, by using Lewis acids such as TMSOTf, N,Ndibenzylated or N,N-diallylated 2,3-epoxy amines, compounds of type 6 have been reported by Rayner and co-workers to rearrange to the aziridinium salts 7 which open at the more reactive C-1 position with various nucleophiles to yield the rearrangement-opening products 8. [9][10][11] For example, the 2,3-epoxy-N,N-diallylamine derivative 6 (R 1 = Pr n , R 2 = H) was treated with TMSOTf to yield the aziridinium salt 7 in quantitative yield. Removal of the trimethylsilyl group of 7 with potassium carbonate in methanol and subsequent intramolecular rearrangement regenerated the original epoxy amine starting material 6 in a high yield.…”

Methods for the Cleavage of Allylic and Propargylic C–N Bonds in Amines and Amides – Selected Alternative Applications of the 1,3‐Hydrogen Shift

“…The cleavage of C–N allylic bonds in N ‐allyl‐ and N , N ′‐diallylamines can be performed in good yields by refluxing the substrate in ethanol in the presence of one equivalent of methanesulfonic acid and a catalytic amount of Pd/C 58,59. The mechanism proceeds as with allyl ethers by migration of the double bond 60.…”