28720-60-7Relevant articles and documents
Stereoselective synthesis of 2,6-: Trans -4-oxopiperidines using an acid-mediated 6- endo-trig cyclisation
Bell, Jonathan D.,Harkiss, Alexander H.,Wellaway, Christopher R.,Sutherland, Andrew
, p. 6410 - 6422 (2018/10/02)
An acid-mediated 6-endo-trig cyclisation of amine-substituted enones has been developed for the stereoselective synthesis of trans-6-alkyl-2-methyl-4-oxopiperidines. Performed under conditions that prevent removal of the Boc-protecting group or acetal formation, the key cyclisation was found to generate cleanly the 4-oxopiperidine products in high overall yields from a wide range of alkyl substituted enones. The synthetic utility of the trans-6-alkyl-2-methyl-4-oxopiperidines formed from this process was demonstrated with the total synthesis of the quinolizidine alkaloid, (+)-myrtine and the piperidine alkaloid, (-)-solenopsin A.
Removal of the pyridine directing group from α-substituted N-(pyridin-2-yl)piperidines obtained via directed Ru-catalyzed sp3 C-H functionalization
Smout, Veerle,Peschiulli, Aldo,Verbeeck, Stefan,Mitchell, Emily A.,Herrebout, Wouter,Bultinck, Patrick,Vande Velde, Christophe M. L.,Berthelot, Didier,Meerpoel, Lieven,Maes, Bert U. W.
, p. 9803 - 9814 (2013/10/22)
Two strategies, "hydrogenation-hydride reduction" and "quaternization-hydride reduction", are reported that make use of mild reaction conditions (room temperature) to efficiently remove the N-pyridin-2-yl directing group from a diverse set of C-2-substituted piperidines that were synthesized through directed Ru-catalyzed sp3 C-H functionalization. The deprotected products are obtained in moderate to good overall yields irrespective of the strategy followed, indicating that both methods are generally equally effective. Only in the case of 2,6-disubstituted piperidines, could the "quaternization-hydride reduction" strategy not be used. The "hydrogenation-hydride reduction" protocol was successfully applied to trans- and cis-2-methyl-N-(pyridin-2-yl)-6-undecylpiperidine in a short synthetic route toward (±)-solenopsin A (trans diastereoisomer) and (±)-isosolenopsin A (cis diastereoisomer). The absolute configuration of the enantiomers of these fire ant alkaloids could be determined via VCD spectroscopy.
Access to 2,6-disubstituted piperidines: Control of the diastereoselectivity, scope, and limitations. applications to the stereoselective synthesis of (-)-solenopsine A and alkaloid (+)-241D
Abrunhosa-Thomas, Isabelle,Plas, Aurelie,Vogrig, Alexandre,Kandepedu, Nishanth,Chalard, Pierre,Troin, Yves
, p. 2511 - 2526 (2013/04/24)
Scope and limitations in the diastereoselective preparation of 2,6-cis or 2,6-trans disubstituted piperidines are described, through intramolecular reaction of chiral β′-carbamate-α,β-unsaturated ketone. This methodology has been applied to the total synthesis of a few well chosen examples, such as (-)-solenopsine A and alkaloid (+)-241D.
