Triflic Acid Promoted Decarboxylation of Adamantane-oxazolidine-2-one: Access to Chiral Amines and Heterocycles

We
have developed a one-step procedure to a variety of chiral lipophilic
and conformationally rigid amines and heterocycles by decarboxylation
of adamantane-oxazolidine-2-one. Triflic acid or aluminum triflate
promote the addition of diverse nucleophiles to the oxazolidine-2-one
moiety accompanied by the release of carbon dioxide. The resulting
amine or heterocycle is then protonated/metalated by the catalyst
(promotor). Additionally, the starting racemic material, adamantane-oxazolidine-2-one,
was resolved into single enantiomers using a chiral auxiliary to access
enantio-enriched products and to study the racemization pathway of
chiral 1,2-disubstituted adamantane derivatives.