239802-22-3

Upstream product

• 239802-21-2 (2S,3S,6S)-2-Benzyloxymethyl-3-hydroxy-6-methoxycarbonylmethyl-piperidine-1-carboxylic acid methyl ester 
• 92912-21-5 ethyl 1-benzyl-3,6-dioxo-2-piperidinecarboxylate 
• 165672-51-5 (5S,6S)-1-Benzyl-5-methoxymethoxy-6-methyl-piperidin-2-one 
• 165672-46-8 (2R,3S)-1-Benzyl-3-hydroxy-6-oxo-piperidine-2-carboxylic acid ethyl ester 
• 165672-49-1 (5S,6S)-1-Benzyl-6-hydroxymethyl-5-methoxymethoxy-piperidin-2-one 
• 165672-48-0 (2R,3S)-1-benzyl-3-methoxymethoxy-6-oxopiperidine-2-carboxylic acid ethyl ester 
• 165672-58-2 (5S,6S)-1-Benzyl-6-benzyloxymethyl-5-methoxymethoxy-piperidin-2-one 
• 165672-59-3 (5S,6S)-1-Benzyl-6-benzyloxymethyl-5-methoxymethoxy-piperidine-2-thione 
• 239802-20-1 [(5S,6S)-1-Benzyl-6-benzyloxymethyl-5-hydroxy-piperidin-(2E)-ylidene]-acetic acid methyl ester 
• 165672-50-4 (5S,6R)-1-Benzyl-5-methoxymethoxy-6-phenylsulfanylmethyl-piperidin-2-one 

Relevant academic research and scientific papers

2-Piperidone type of chiral building block for 3-piperidinol alkaloid synthesis

An enantiomeric pair of a new 2-piperidone type of chiral building block (1) has been prepared by bakers' yeast reduction of β-keto ester (2) or lipase-mediated transesterification of hydroxy ester (±)-(1), derived from NaBH4 reduction of 2, in enantiopure form. The absolute stereochemistry of (-)-1 was verified by its conversion to known piperidine (-)-3, an intermediate for the synthesis of (-)-spectaline. The 2-piperidone (-)-1 was converted to all four diastereomers of 2,6-disubstituted 3-piperidinol chiral building blocks on the basis of homologation of (-)-1 at the lactam carbonyl using the Eschenmoser method via corresponding thiolactams (-)-9, (-)-20, (- )-25, (-)-27, and (-)-34, followed by stereocontrolled reduction of the resulting vinylogous urethanes (+)-10, (+)15, (+)-23, (+)-28, and (+)-32, respectively, and epimerization of the hydroxyls at the 3-position [(-)-16 via (+)-17 to (-)-18 and (+)-29 via (+)-30 to (+)-31]. The versatility of these chiral building blocks has been demonstrated by the chiral synthesis of the 3-piperidinol alkaloids (+)-prosafrinine, (-)-iso-6-cassine, (-)- prosophylline, and (-)-prosopinine from (-)-37, (-)-14, (+)-36, and (-)-26, respectively.

Enantio- and diastereodivergent synthesis of all four diastereomers of the 2,6-disubstituted 3-piperidinol chiral building block

Enantio- and diastereodivergent synthesis of all four diastereomers of 2,6-disubstituted 3-piperidinol has been achieved. The versatility of these compounds as the chiral building block for alkaloid synthesis has been demonstrated both by total synthesis of iso-6-cassine and by formal synthesis of prosopinine, cassine, and spectaline.