1026470-49-4

Upstream product

• 259856-84-3 (2R)-1-(tert-butyldimethylsilyloxy)-4-(1,3-dithian-2-yl)-4-phenyl-2-butanol 
• 259856-85-4 (2S)-4-(1,3-dithian-2-yl)-1,2-epoxy-4-phenylbutane 
• 259856-82-1 (3R)-3-hydroxy-5-oxo-5-phenylpentanenitrile 
• 5425-44-5 2-Phenyl-[1,3]dithiane 
• 326477-55-8 (4S,6S)-(-)-4-Hydroxy-6-phenylpiperidin-2-one 
• 326477-54-7 6-phenyl-5,6-dihydro-2,4(1H,3H)-pyridinedione 
• 158109-78-5 (R,E)-N-benzylidene-4-methylbenzenesulfinamide 
• 407-25-0 trifluoroacetic anhydride 
• 259856-83-2 (2S,4R)-(-)-2-Phenylpiperidine-4-ol 
• 259856-86-5 (3R)-5-(1,3-dithian-2-yl)-3-hydroxy-5-phenylpentanenitrile 
• 326477-52-5 Methyl (R_S,S)-(-)-3-oxo-5-phenyl-5-(p-toluenesulfinylamino)pentanoate 

Downstream Products

• 1844-40-2 (2S,4R)-4-hydroxypiperidine-2-carboxylic acid 
• 259856-87-6 (2S,4R)-(-)-4-Acetoxy-2-phenyl-1-trifluoroacetylpiperidine 

Relevant academic research and scientific papers

Asymmetric synthesis of the four stereoisomers of 4-hydroxypipecolic acid

The asymmetric synthesis of all four stereoisomers of 4-hydroxypipecolic acid (1) from the polyfunctionalized chiral building blocks δ-amino β-keto esters (S(S),R)-(+)-5 or (R(S),S)-(-)-5 is described. Key steps in the synthesis are the stereoselective reductions of b-phenylpiperidine-2,4-dione (6) and N-sulfinyl δ-amino β-keto esters 5 to cis 4-hydroxy 2-piperidinone 7 and syn-δ-amino β-hydroxy ester 9, respectively. The only protecting/deprotecting group chemistry required is related to the oxidation step.

A new route to (2S,4R)- and (2R,4S)-4-hydroxypipecolic acid

Both enantiomers of cis-4-hydroxypipecolic acid have been prepared by asymmetric synthesis using (S)- or (R)-glycidol as the chiral source, and involving a stereoselective hydrogenation of a six-membered cyclic imine. The latter is obtained by reduction and cyclization of a cyano β-hydroxy ketone.