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Indolizidine synthesis by transannular cyclization
Author(s) -
Wilson Stephen R.,
Sawicki Robert A.
Publication year - 1982
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570190114
Subject(s) - chemistry , beckmann rearrangement , stereospecificity , indolizidine , steric effects , alkyl , ring (chemistry) , stereochemistry , solvent , nmr spectra database , medicinal chemistry , organic chemistry , oxime , alkaloid , spectral line , catalysis , physics , astronomy
Beckmann rearrangement of alkylcyclooctenone oximes VIa and VIb gave corresponding nine‐membered lactams 1,3,4,5,8,9‐hexahydro‐3‐methyl‐2 H ‐azonin‐2‐one (VIIIa) and 1,3,4,5,8,9‐hexahydro‐3‐butyl‐2 H ‐azonin‐2‐one (VIIIb), respectively. A stereospecific transannular cyclization was induced by mercuric acetate leading to alkyl indolizinones Xa and Xb. Temperature and solvent dependent nmr spectra of the medium ring lactams indicates the stereochemical control is caused by steric interactions of the alkyl side chain. Lithium aluminum hydride reduced Xa/Xb to cis ‐octahydro‐6‐methylindolizidine (XIa) and cis ‐octahydro‐3‐ n ‐butylindolizidine (XIb).