The regioselective and diastereoselective cyclization of acyliminium
intermediates generated from aminocyclopropanes on unprotected indoles
is presented. The recent results obtained in our group are compared
with previous intermolecular reactions with aminocyclopropanes as
well as with other cyclization methods involving iminium ions and
unprotected indoles. A first speculative analysis of possible reaction
mechanisms allows rationalizing the observed selectivity. The high
potential of the method for the synthesis of natural alkaloids is
demonstrated in the formal synthesis of aspidospermidine and the
total synthesis of goniomitine.
alkaloids - cyclization - indoles - iminium - aminocyclopropanes