Facile Synthesis of 4-Piperidones by Condensation of an α,β-Unsaturated Ketone, an Aldehyde and Ammonia: Synthesis of the<i>Dendrobatid</i>Frog Alkaloid 241D
作者:Michael W. Edwards、H. Martin Garraffo、John W. Daly
DOI:10.1055/s-1994-25665
日期:——
A one-step reaction of an α,β-unsaturated ketone (3-penten-2-one, 1), an aldehyde (decanal, 2) and an amine (ammonia) afforded mainly the cis-isomer of (±)-2-methyl-6-nonyl-4-piperidone (3). Sodium borohydride reduction afforded as the major product (±)-cis,cis-4-hydroxy-2-methyl-6-nonylpiperidine (4), identical in NMR and IR spectra to the (+)-piperidine 241D isolated from skin extracts of a dendrobatid frog. The reaction was shown to be generally applicable for the synthesis of 2,6-disubstituted 4-piperidones.
Access to 2,6-Disubstituted 4-Oxopiperidines Using a 6-<i>Endo</i>-<i>trig</i> Cyclization: Stereoselective Synthesis of Spruce Alkaloid and (+)-241D
作者:Alexander H. Harkiss、Andrew Sutherland
DOI:10.1021/acs.joc.7b02799
日期:2018.1.5
providing the corresponding 4-oxopiperidines in high yields (80–89%). Stereoselective reduction of the 2,6-cis-disubstituted 4-oxopiperidines then gave the 2,4,6-cis,cis-trisubstituted 4-hydroxypiperidines in high diastereoselectivity. The general nature of this approach was demonstrated with the synthesis of the natural products, spruce alkaloid and (+)-241D.