A convenient, efficient, one-pot strategy for the synthesis of structurally diverse
trifluoromethylated spirotetrahydropyridine-3-carboxylate derivatives is disclosed
by taking advantage of a four-component reaction involving arylidene isoxazol-5-ones,
aromatic aldehydes, ethyl 4,4,4-trifluoro-3-oxobutanoate and ammonium acetate. Additionally,
a more consecutive approach to the same products is achieved via a one-pot, multicomponent
reaction. The protocol allows easy access to trifluoromethylated spiroheterocycles
in moderate to good yields under mild and catalyst-free conditions.
Key words
fluorinated heterocycles - Michael addition - spiropiperidines - catalyst-free - multicomponent
reactions