Ammonium-Directed Oxidation of Cyclic Allylic and Homoallylic Amines

Abstract

The ammonium-directed olefinic oxidation of a range of cyclic allylic and homoallylic amines has been investigated. Functionalization of a range of allylic 3-(N,N-dibenzylamino)cycloalk-1-enes with m-CPBA in the presence of Cl(3)CCO(2)H gives exclusively the corresponding syn-epoxide for the 5-membered ring (>99:1 dr), the anti-epoxide for the 8-membered ring (>99:1 dr), and predominantly the anti-epoxide for the 7-membered ring (94:6 dr). Oxidation of the homoallylic amines 3-(N-benzylamino)methylcyclohex-1-ene and 3-(N,N-dibenzylamino)methylcyclohex-1-ene gave, in both cases, the corresponding N-protected 1,2-anti-2,3-syn-3-aminomethylcyclohexane-1,2-diol with high levels of diastereoselectivity (>or=90:10 dr). The versatile synthetic intermediates resulting from these oxidation reactions are readily transformed into a range of amino diols.

Regio- and stereoselective synthesis of new diaminocyclopentanols

“…The same relative configuration of 8d was assigned from 2D NMR analysis, and the stereochemistry of 8b and 8c was additionally confirmed by the comparison of 3 J coupling constants of the resonances corresponding to C(1)H, C(2)H and C(5)H (Supporting Information File 2). Therefore, spectral data obtained for the compounds 8a–d are consistent with the acid-catalyzed trans -diaxial epoxide opening, proceeding via a late-transition state, and the N -benzyl- N -methylammonium moiety promotes the nucleophilic attack at the C1-oxirane carbon atom [29]. …”

“…Epoxides 6a,b were synthesized from 3a,b through epoxide ring inversion using glacial acetic acid as the oxirane-cleaving agent [29]. …”

Stereoselective synthesis of carbocyclic analogues of the nucleoside Q precursor (PreQ0)

“…We chose the benzoate protecting group to generate UV–visible intermediates and because its ease of cleavage under basic conditions would converge with the final pivalamide deprotection step. We adapted this protecting group strategy to Bond’s synthetic route since it was the most concise and diastereospecific available [30] (Fig. 4).…”

Epoxide ring-opening approach to the synthesis of diverse trisubstituted cyclopentanes

“…Compound 4. Yellow oil, yield 60%, 1.38 g. 1 (10). Nitrile 4 (0.60 g, 2.5 mmol) was dissolved in 2 mL of 30% water solution of sulfur acid.…”