In this work, we describe the synthesis of chiral (R)-(‒)-piperidine-2,4-dione derived from (R)-(‒)-phenylglycinol, a valuable building block for the diastereoselective synthesis of piperidine alkaloids. The key step involves intramolecular cyclization: when the electrophile is an ester, the reaction proceeds via the formation of a Grignard intermediate, whereas when the electrophile is a nitrile, the cyclization follows a Blaise-type mechanism.
Herein, starting from (R)-(+)-α-methylbenzylamine, we report an efficient synthesis and full characterization of a new (R)-3-(1-hydroxyethylidene)-1-(1-phenylethyl)piperidine-2,4-dione, a new tetramic acid analog. The key steps involved a non-classical Corey–Chaykovsky intramolecular cyclization reaction to access the corresponding zwitterion, followed by a sequential desulfurization/reduction and condensation procedure. The titled product was obtained in five steps, and the desired product 7 with an overall 58% yield.
Herein, starting from (R)-(+)-α-methylbenzylamine, we report an efficient synthesis and full characterization of a new (R)-3-(1-hydroxyethylidene)-1-(1-phenylethyl)piperidine-2,4-dione, a new tetramic acid analogue. The key steps involved a non-classical Corey-Chaykovsky intramolecular cy-clization reaction to access the corresponding zwitterion, followed by a sequential desul-furization/reduction and condensation procedure. The key intermediate was obtained in 5 steps, and the desired product 7 with an overall 58% yield.