3-Piperidinol alkaloids synthesis

With the enantiomeric pair of 1 in hand, we examined the stereodivergent synthesis of a,a -disubstitued 3-piperidinol alkaloids. The basic strategy we used to prepare the building blocks (I-IV) from (-)-1 is presented in Figure 3. 

Fig. (3). Basic strategy for the stereodivergent synthesis of 3-piperidinol alkaloids...

Finally, the type IV chiral building block 15 was synthesized via the iminium reduction of the corresponding iminiun salt derived from the vinylogous urethane 14 as shown in Scheme 5. With all four stereoisomers of the chiral building blocks (I IV) for synthesis of 3-piperidinol alkaloid in hand, we examined the synthesis of prosafrinine,... 

The reactions depicted in Scheme 39 were already conducted in view of a potential use in the synthesis of pyrrolidinols and piperidinols. The structural feature of a 2-arylmethyl-3-hydroxysubstitution is not only found in preussin but also in anisomycin (152) [87] or in the piperidine alkaloid FR 901483 (153) [88] (Fig. 5). 

Synthesis of new 3-piperidinol-type chiral building blocks and their application to the alkaloids syntheses 99YGK1075. 

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