148855-27-0Relevant articles and documents
α-N-Acyliminium Ion - 2-Bromoalkene Cyclizations.
Gesson, Jean-Pierre,Jacquesy, Jean-Claude,Rambaud, Didier
, p. 2239 - 2248 (1993)
The cylization of α-N-acyliminium ions generated from ethoxylactams 1-3 using trifluoroacetic acid, trifluoromethanesulfonic acid and anhydrous HF affords ketones, bromoalkenes and geminal bromofluoro compounds, respectively.A non concerted process explains these results which demonstrate the high reactivity of the intermediate bromocarbenium ions with different nucleophiles.The unexpected fluorination observed in HF is also observed with simple alkenes which give mixtures of epimeric fluoro derivatives.
Synthesis of Azabicycles via Cascade Aza-Prins Reactions: Accessing the Indolizidine and Quinolizidine Cores
Chio, Freda K. I.,Guesné, Sébastien J. J.,Hassall, Lorraine,McGuire, Thomas,Dobbs, Adrian P.
, p. 9868 - 9880 (2015/11/03)
The first detailed studies of intramolecular aza-Prins and aza-silyl-Prins reactions, starting from acyclic materials, are reported. The methods allow rapid and flexible access toward an array of [6,5] and [6,6] aza-bicycles, which form the core skeletons of various alkaloids. On the basis of our findings on the aza-Prins and aza-silyl-Prins cyclizations, herein we present simple protocols for the intramolecular preparation of the azabicyclic cores of the indolizidines and quinolizidines using a one-pot cascade process of N-acyliminium ion formation followed by aza-Prins cyclization and either elimination or carbocation trapping. It is possible to introduce a range of different substituents into the heterocycles through a judicial choice of Lewis acid and solvent(s), with halo-, phenyl-, and amido-substituted azabicyclic products all being accessed through these highly diastereoselective processes.
