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Title: | Synthesis of the necine bases (±)-macronecine and (±)-supinidine via an aza-ene reaction and allylsilane induced ring closure |
Authors: | Sarkar, T K Hazra, A Gangopadhyay, P Panda, Niranjan Slanina, Z Chun-Cheng, Lin Hui-Ting, Chen |
Keywords: | Aza-ene reaction Heterocyclic allylsilanes Fused tetrahydropyrazole Necine bases Supinidine Macronecine |
Issue Date: | 2005 |
Publisher: | Elsevier |
Citation: | Tetrahedron, Vol 61, Iss 5, P 1155-1165 |
Abstract: | An aza-ene reaction has been used for the first time for the synthesis of two 5-membered lactam-hydrazides, each with a built-in allylsilane terminator for further elaboration. One of the lactam-hydrazides was transformed via an allylsilane-hydrazonium ion ring closure to a fused tetrahydropyrazole which may be considered as a mono-nitrogen analog of the biologically significant necine bases. A density functional theoretical study (B3LYP/6-21G*) was undertaken to provide insight into the factors that favor a synclinal transition structure of the hydrazonium ion intermediate leading to the tetrahydropyrazole. This stereocontrolled synthesis served as a model for the multi-step conversion of the other lactam-hydrazide, the substituted 2-pyrrolidinone, to necine bases (±)-supinidine and (±)-macronecine. An allylsilane-aldehyde ring closure formed the key step in the synthesis of these natural products. |
Description: | Copyright for the published version belongs to Elsevier |
URI: | http://dx.doi.org/10.1016/j.tet.2004.11.046 http://hdl.handle.net/2080/516 |
Appears in Collections: | Journal Articles |
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