Preparation of enantiopure substituted piperidines containing 2-alkene or 2-alkyne chains: application to total syntheses of natural quinolizidine-alkaloids.
A general method for the preparation of enantiopure 2-alkene- or 2-alkyne-containing chain substituted piperidines was established by using nonracemic Betti base as a chiral auxiliary. The key step is that the auxiliary residue was removed by a novel base-catalyzed N-debenzylation via a formation of o-quinone methide mechanism in stead of the traditional hydrogenolysis, by which the alkene or alkyne groups survived. By this method, ten 2-alkene- or 2-alkyne-containing chain substituted piperidines were prepared on the gram scale within a few hours. To demonstrate the efficiency of the method and the versatility of the product, total syntheses of natural alkaloids (+)-pelletierine, (-)-lasubine II, and (+)-cermizine C were achieved by using (S)-2-allyl-N-Boc-piperidine as a versatile building block.
Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
Guolin
G
Cheng
Xinyan
X
Wang
Deyong
D
Su
Hui
H
Liu
Fei
F
Liu
Yuefei
Y
Hu
D000470:Alkaloids / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D006574:Heterocyclic Compounds, 2-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010880:Piperidines / Q000138:chemical synthesis* / Q000737:chemistry; D054837:Quinolizidines / Q000138:chemical synthesis* / Q000737:chemistry; D011807:Quinolizines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D000470:Alkaloids; D000475:Alkenes; D000480:Alkynes; D006574:Heterocyclic Compounds, 2-Ring; D010880:Piperidines; D054837:Quinolizidines; D011807:Quinolizines; C518697:cermizine C; C414385:lasubin I; C008195:isopelletierine