251995-69-4Relevant academic research and scientific papers
An efficient approach to 2-substituted N-tosylpiperdines: asymmetric synthesis of 2-(2-hydroxy substituted)piperidine alkaloids
Bisai, Alakesh,Singh, Vinod K.
, p. 1907 - 1910 (2007/10/03)
We have developed an efficient and a general approach to chiral 2-substituted N-tosylpiperidines starting from chiral α-substituted-N-tosylaziridines. Using this approach, we have synthesized (+)-coniine. The synthesis of chiral N-tosyl-2-piperidinylethanol 15 and ent-15, was achieved from l- and d-aspartic acids, respectively in few steps. Piperidine 15 was converted into 2-(2-hydroxysubstituted)piperidines of type 2 in optically active form. By applying this strategy, asymmetric syntheses of halosaline (R,R)-2a, (+)- and (-)-sedamine 2b, (+)- and (-)-allosedamine 2c, (+)- and (-)-sedridine 2d, (+)- and (-)-allosedridine 2e, (+)-tetraponerine T-3 3a, T-4 3c, T-7 3b, and T-8 3d have been achieved in high yields. These stereoisomers can be interconverted via Mitsunobu inversion in excellent yields.
A new synthesis of all four stereoisomers of 2-(2,3- dihydroxypropyl)piperidine via iterative asymmetric dihydroxylation to cause enantiomeric enhancement. Application to asymmetric synthesis of naturally occurring piperidine-related alkaloids
Takahata, Hiroki,Kubota, Minoru,Ikota, Nobuo
, p. 8594 - 8601 (2007/10/03)
Both enantiomers of 2-(2-propenyl)piperidine 1 (76-88% ee), prepared via the first asymmetric dihydroxylation (AD) of 5-hexenyl azide, underwent the second AD to provide all four of the stereoisomeric 2-(2,3- dihydroxypropyl)piperidines 2 with enantiomeric enhancement.(>98% ee). An asymmetric synthesis, starting from 2, of several 2-(2- hydroxyalkyl)piperidine alkaloids [(-)halosaline, (+)-N-methylallosedridine, (+)-8-ethylnorlobelol, (+)-sedridine, (+)-allosedridine, (-)allosedridine, and (+)-N-methylsedridine] and the ant defense alkaloids [(+)-tetraponerine-3 (T-3), T-4, T-7, and T-8] is demonstrated.
