139163-21-6Relevant articles and documents
Straightforward access to enantioenriched 2-allylpiperidine: Application to the synthesis of alkaloids
Bosque, Irene,González-Gómez, José C.,Foubelo, Francisco,Yus, Miguel
, p. 780 - 784 (2012)
An efficient stereocontrolled preparation of (2R,RS)-2-allyl-(N- tert-butylsulfinyl)piperidine and its enantiomer is detailed. The sequence requires only two synthetic operations with one-column chromatography and is readily scaled up. The versatility of these chiral building blocks was exemplified by the total or formal synthesis of some natural and unnatural alkaloids.
Polymer-supported (-)-8-phenylmenthyl auxiliary as an effective solidphase chiral inductor in the addition of nucleophiles to N-acyliminium Ions
Forero-Doria, Oscar,Santos, Leonardo S.,Nachtigall, Fabiane M.,Shankaraiah, Nagula
, p. 696 - 702 (2018/02/27)
Aim and Objective: According to our interest in developing new methods for the construction of intricate molecules, a reliable polymer-supported (-)-8-phenylmenthyl chiral auxiliary for the addition of different nucleophiles to chiral-supported N-acyliminium precursors were developed. Material- and Method-: Merrifield resin was employed to anchor (-)-8-phenylmenthol, which was prepared by nitration of (-)-8-phenylmenthyl chloroacetate followed by reduction of nitro group and subsequent Merrifield resin coupling. Treatment of a suspension of polymer-supported chloroformate and piperidinone in the presence of Et3N resulted in attachment of the substrate onto the solid-support. Treatment of the resulting resin with LiEt3BH/MeOH afforded methoxypiperidine in 87% yield. Then, the addition of allyltrimethylsilane, TMSCN, 2-(trimethylsiloxy)propene and triisopropylsilyloxyfuran and others to the N-acyliminium ion derived from chiral 2-methoxypiperidine carbamate was studied. Results: The stereochemical outcome of the addition of nucleophiles to the supported N-acyliminium ion derived from 2-methoxypiperidine carbamate was proposed through the Si-face, affording after resin cleavage 2-substituted piperidines in 70%-84% yields and selectivities ranging from 4:1-11.1. Moreover, the key intermediates of chiral piperidines have been employed for the synthesis of simple chiral alkaloids such as (R)-pipecolic acid, (R)-pelletierine, (S)-coniine and (R,R)-myrtine. Conclusion: The proposed supported-chiral auxiliary for asymmetric approach may be expected to result not only in efficient solid-phase syntheses of a wide range of alkaloids but also in the development of useful new solid-phase methodologies, particularly for the asymmetric additions to iminium precursors. This work describes the first example of solid-phase synthesis by using supported (-)-8-phenylmenthyl as an effective chiral inductor and would be useful for the synthesis of chiral building block libraries.
Solid-phase synthesis of piperidines by N-acyliminium ion chemistry
Veerman, Johan J. N.,Klein, Jasper,Aben, Rene W. M.,Scheeren, Hans W.,Kruse, Chris G.,Van Maarseveen, Jan H.,Rutjes, Floris P. J. T.,Hiemstra, Henk
, p. 3133 - 3139 (2007/10/03)
An efficient solid-phase procedure for the synthesis of a number of 2-substituted piperidines is reported. Starting from solid-supported carbamate -tethered δ-amino acetals, 2- benzotriazolyl- substituted (Bt-substituted) piperidines were obtained by acid-induced ring-closure followed by trapping of the transient N-acyliminium ions with benzotriazole. These 2-Bt-substituted piperidines were then used as precursors for the successful introduction of several C-nucleophiles by N-acyliminium ion chemistry. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
