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Org Biomol Chem
; 19(7): 1610-1615, 2021 02 25.
Article
in English
| MEDLINE
| ID: mdl-33528484
ABSTRACT
Highly enantiopure and bioactive δ-valerolactones and pyrazolones, bearing α-all-carbon quaternary stereocentres, were successfully and sequentially prepared via a one-pot procedure starting from readily available, inexpensive materials, catalysed by a new chiral squaramide under mild reaction conditions. An organocatalytic Michael reaction afforded the valerolactones, while a one-pot Michael-hydrazinolysis-imidization cascade yielded the pyrazolones. This procedure is economically efficient and environmentally benign.